Effects of Alternatives on Selected Noxious Weeds

and Cheatgrass on Rangeland

Invasions of exotic plants have been numerous in

the Basin in the last 100 years (Young and others

1972, Franklin and Dryness 1973, Yensen 1981,

in: Mack 1986). On the Basin's rangeland, exotic

plants, especially the legally declared "noxious"

weeds, and cheatgrass are spreading rapidly and in

some cases exponentially. Their establishment and

spread is aided by disturbance to the soil surface

in combination with their opportunistic life cycle

strategies.

The establishment and spread of noxious weeds

and cheatgrass is of concern because of their

adverse effects on rangeland health, which

include:

• Reduction of the diversity and abundance of

native vegetation.

• Reduction of forage for livestock and wildlife.

• Reduction in the diversity and quality of wildlife

habitat.

• Increase in erosion and subsequent decrease in

water quality and soil productivity.

Although noxious weed establishment and spread

is facilitated by soil surface disturbance, some

noxious weed species (such as spotted knapweed,

yellow starthistle, and leafy spurge) are invading

relatively undisturbed sites, including wilderness

areas and National Parks (Asher 1994; Tyser and

Key 1988).1

The extent and effects of noxious weeds and

cheatgrass on rangeland health are an issue of critical concern in the Basin, and for this reason are

addressed in the preliminary draft EISs and also

included in this evaluation of alternatives.

Scientific names of weed species discussed in this

evaluation are listed in table 2.41.

Methods Used in Evaluating the

Effects of Alternatives on Noxious

Weeds and Cheatgrass

The following steps formed the foundation for

evaluating the effects of the alternatives on selected noxious weeds and cheatgrass:

• First, the noxious weeds and cheatgrass analyzed

in Karl and others (1995) were categorized by

range cluster, giving current location within the

cluster and any current acreage data, where

available (appendix 2L, tables 2L. 1 through

2L.6). A list was made of potential vegetation

types (PVTs) that had either high or moderate

susceptibility to these weeds within the dry

grass, dry shrub, and cool shrub potential vegetation groups (PVGs) (appendix 2M, tables

2M.1 through 2M. 10).

A high-susceptibility potential vegetation type is

defined as a type where a weed species can

invade successfully and become dominant or

codominant, even in the absence of intense or

frequent disturbance. A moderate-susceptibility

potential vegetation type is defined as a type

where a weed species can invade successfully

because intense or frequent disturbance impacts

the soil surface or removes the normal canopy

cover.

See Karl and others (1995) for a table listing the

susceptibility ratings for each rangeland potential vegetation type in the Basin to each noxious

weed and cheatgrass. Susceptibility ratings of

rangeland potential vegetation types were com-

'Personal observation. 1996. M.G. Karl. Rangeland Management Specialist - Ecologist. U.S. Department of Agriculture, Forest

Service. Interior Columbia Basin Ecosystem Management Project, Walla Walla, Washington.

Landscape Ecology 243
piled from B. Anderson,2

 Asher (1991, 1993a,

1993b),3 Brandt and Rickard (1994), Karl and

others (1995), Pellant and Hall (1994), Piper

and Coombs (1996), Rice and others (1994),

Roche (1991, 1994), and USDI (1996). These

susceptibility ratings, along with the weed

species most prevalent within a PVG and range

cluster (appendix 2L, tables 2L. 1 through 2L.6)

were used to make determinations of the weed

species that would be the target of weed control

activities. It should be noted that the acreages in

appendix 2L are not specific in all cases to

BLM- and FS-administered lands, and that the

estimate areas in most cases are general. Further

refinement may occur after more accurate data is

compiled from the various BLM districts and

resource areas and the forests and ranger districts

in the EIS implementation process.

• Second, the rangeland potential vegetation types

in each subbasin (4th-field HUC) within the

Basin were summed by range cluster for the

BLM- and FS-administered lands and for Other

lands (non BLM/FS; incomplete information

not presented for all clusters) (appendix 2M,

tables 2M.1 through 2M.10). These data were

used as background material in determining the

extent of moderate and high susceptibility

potential vegetation types within each cluster.

• Third, the management activity tables in the

preliminary draft EISs for the Eastside and the

Upper Columbia River Basin areas were used to

provide estimates of acres on which weed control, livestock management, and prescribed

burning activities would be implemented for

each alternative. Acreage for weed control and

livestock management was specified by dry

grass, dry shrub, and cool shrub potential vegetation groups for each target range cluster for

each alternative (appendix 2N, tables 2N. 1

through 2N.6). Tables in appendix 2N also

include the steps of Integrated Weed Management (IWM) and affected PVTs. Chapter 3 of

the preliminary draft EISs was the origin of the

IWM emphasis.

• Fourth, die alternatives described in Chapter 3 of

the preliminary draft EISs, including their Integrated Weed Management (IWM) emphasis,

were the basis for this evaluation of effects of the

alternatives on noxious weeds and cheatgrass. The

steps of integrated weed management emphasized

in the EISs vary by range cluster, according to the

different objectives or emphasis of each alternative. These objectives are either restore, produce,

conserve, or various combinations.

The alternatives were ranked for their effectiveness

in preventing the spread of noxious weeds and

cheatgrass in the dry grass, dry shrub, and cool

shrub PVGs. Ranks of effectiveness are presented

in tables in the following text. This ranking was

done by potential vegetation group and EIS planning area; finer-scale information such as the

susceptibility of each weed species to chemical,

biological, manual, and mechanical control techniques (Karl and others 1995); and the assumptions listed below.

The overall numerical rank assigned to each alternative for a discussion of effects was computed as

the average of the range clusters' ranks.

Assumptions for Rangelands

Rangeland Assumption 1: The basis for the noxious weed and cheatgrass evaluation was the dry

grass, dry shrub, and cool shrub potential vegetation groups described in management activity

table 3-7 of the preliminary draft EISs. No other

potential vegetation groups were included in this

evaluation. Although the forest and riparian PVGs

were not analyzed, due to lack of time, the information for the cool shrub PVG is somewhat useful as a proxy.

2

Personal communication. 1995. Bruce Anderson, U.S. Department of Agriculture, Forest Service, Nez Perce National Forest,

Salmon River/Slate Creek Ranger District, Whitebird, Idaho.

'Also personal communication. 1996. Jerry Asher, Natural Resource Specialist, U.S. Department of Interior, Bureau of Land

Management, Oregon State Office, Portland, Oregon.

244 Landscape Ecology
Table 2.41 — Scientific names of weed species referenced in the evaluation of alternatives.

Weed Species Scientific Name

Cheatgrass

Whitetop

Musk thistle

Purple starthistle

Diffuse knapweed

Iberian starthistle

Spotted knapweed

Russian knapweed

Yellow starthistle

Squarrose knapweed

Rush skeletonweed

Canada thistle

Common crupina

Leafy spurge

Halogeton

Spiny cocklebur

Orange hawkweed

Yellow hawkweed

St. Johnswort

Dyers woad

Perennial pepperweed

Dalmatian toadflax

Purple loosestrife

Matgrass

Scotch thistle

African rue

Sulfur cinquefoil

Mediterranean sage

Tansy ragwort

Medusahead

Saltcedar

Syrian bean-caper

Bromus tectorum

Cardaria spp.

Carduus nutans

Centaurea calcitrapa

Centaurea diffusa

Centaurea iberica

Centaurea maculosa

Centaurea repens

Centaurea solstitialis

Centaurea virgata

Chondrilla juncea

Cirsium arvense

Crupina vulgaris

Euphorbia esula

Halogeton glomeratus

Xanthium spinosum

Hieracium aurantiacum

Hieracium pratense

Hypericum perforatum

/safe tinctoria

Lepidium latifolium

Linaria dalmatica

Lythrum salicaria

Nardus stricta

Onopordum acanthium

Peganum harmala

Potentilla recta

Salvia aethiopis

Senecio jacobaea

Taeniatherum caput-medusae

Tamarix ramosissima

Zygophyllum fabago

Sources of nomenclature: Hitchcock and Cronquist (1976) and Whitson and others (1991).

A potential vegetation group (PVG) is defined as

potential vegetation types (PVTs) that are grouped

on the basis of similar successional response to

disturbance. A potential vegetation type is defined

by the dominant vegetation that will potentially

grow on a site in the absence of disturbance.

Exotic weed invasion was assumed to be a disturbance that potentially would prevent attainment

of a potential vegetation type on a site. Exotic

weed invasion can disrupt vegetation succession

on a site by displacing native vegetation and either

reducing or eliminating the seed bank of native

species, thus preventing succession from proceeding to the potential vegetation type.

Rangeland Assumption 2: A rank is a numerical

prediction of the effectiveness of an alternative to

prevent further infestation of a potential vegetation group by noxious weeds and cheatgrass in the

next 100 years. Ranks ranged from 0 to 3, with

their effectiveness being as follows:

Landscape Ecology 245
Ranks of 0 to 1: Low effectiveness

Ranks of greater-than-1 to 2: Moderate

effectiveness

Ranks of greater-than-2 to 3: High effectiveness

A high rank represents a prediction for prevention

of further infestation and some decline in the

area! extent of noxious weeds and cheatgrass within a PVG. The decline in areal extent of noxious

weeds and cheatgrass increases as the rank

approaches 3. Ranks of 2 or less represent predictions of further infestation of the potential vegetation group. As the rank decreases toward 0, more

of the potential vegetation group is at risk of invasion by weeds.

Rangeland Assumption 3: For noxious weed control efforts to be of some benefit to biodiversity

and productivity of native rangeland plant communities, some of the acreage proposed for "Livestock Management" activity in table 3-7 in the

preliminary draft EISs is assumed to be directed

to the same land base as the acreage proposed for

noxious weed control in the "Improve Rangelands" activity. Attention to proper livestock management post-weed control can aid in preventing

or slowing reinvasion by noxious weeds and

cheatgrass.

Rangeland Assumption 4: Some acreage included

in the Prescribed Burning activity in table 3-7 in

the preliminary draft EISs is assumed to apply to

weed control, either directly or indirectly, depending on the weed species within the range clusters.

For example, prescribed burning can be used to

control medusahead and cheatgrass if the treatment is implemented at the vulnerable phenological stage of the weed. Prescribed burning for control of woody species can either benefit weed control or enhance weed spread, depending on timing

of the burn.

Rangeland Assumption 5: For purposes of this

document, the weed species assessed by Karl and

others (1995) that are presented in appendix 2L,

tables 2L. 1 through 2L.6, and discussed in this

evaluation, are considered the primary weeds to be

targeted for weed control. However, other noxious

weeds that are present and located in the project

area would also be assumed to be a priority for

IWM.

Further, although cheatgrass is not legally declared

noxious in the Basin, the alternatives and the

IWM strategy are assumed to address cheatgrass as

an undesirable weed. Acreages proposed for control efforts in the "Improve Rangelands" activity

in table 3-7 in the preliminary draft EISs are

assumed to include cheatgrass.

Rangeland Assumption 6: The midpoint of the

range of acres in the activities specific to "Improve

Rangelands," "Livestock Management," and

"Prescribed Burning" in table 3-7 of the preliminary draft EISs are assumed to be the maximum

areas directed toward weed control.

There are some inconsistencies between the

Effectiveness of Alternatives discussions in the following text and those listed in appendix 2N,

tables 2N.1 through 2N.6. Acres referenced in

this evaluation were compiled from the February

1996 version of DEIS, whereas acres in appendix

2N present modified acreage figures from later

DEIS analysis. These modified acreage figures

were not available when rankings were made.

Inconsistencies are most noticeable for range clusters 2, 3, and 4, and are noted in the text.

Rangeland Assumption 7: All alternatives direct

IWM efforts first to high disturbance areas, which

typically include roads, waterways, campgrounds,

and trails.

Rangeland Assumption 8: Any noxious weeds

already present in proposed reserves in Alternative

7 are assumed to continue to spread, but at a slower rate than uncontrolled spread outside reserves.

Reserves, especially in range cluster 4, are typically

areas that are fragmented, of relatively small size,

and often surrounded by private land, including

some used for agricultural purposes. The agricultural land, in particular, can be a source of noxious

weed invasion on rangeland. There is a greater

likelihood for noxious weeds to continue invading

and spreading into reserves on these fragmented

areas, compared with less fragmented, more contiguous blocks of land within reserves.

246 Landscape Ecology
Rangeland Assumption 9: Assumptions were

made about the steps of IWM applicable to each

range cluster, according to the cluster's specific

objective or emphasis (table 2.42).

Discussions on Effectiveness of

Alternatives in Integrated Weed

Management

The following discussion focuses on the ranks

used in evaluating the effectiveness of alternatives

to prevent further weed infestation. The evaluation is specific to the dry grass, dry shrub, and

cool shrub potential vegetation groups in the six

range clusters within the Eastside and Upper

Columbia River Basin EIS areas. Information is

organized by the three potential vegetation groups

(dry grass, dry shrub, and cool shrub), then within each of these PVGs by alternatives, EIS area,

and range cluster. Each potential vegetation group

discussion also includes a table presenting the

ranks of effectiveness (tables 2.43-2.48).

Dry Grass Potential Vegetation Group, EEIS

Each alternative's effectiveness in preventing

further infestations of the dry grass potential vegetation group in the Eastside EIS area is ranked by

range cluster and alternative in table 2.43.

Alternatives 1, 2, and 5 Effectiveness

(Dry Grass, EEIS)

Overall rank: 0.17, at the low end of Low effectiveness.

Effectiveness in preventing further infestation of

dry grass:

Range cluster 4: Limited

Other range clusters: Poor

Acreages projected for weed control in Alternatives 1, 2, and 5 would be inadequate to prevent

the spread of noxious weeds and their further

infestation in the dry grass PVG.

Alternative 3 Effectiveness (Dry Grass, EEIS)

Overall rank: 1.21, near the lower end of Moderate effectiveness; slightly lower than Alternative 4.

Effectiveness in preventing further infestation of

dry grass:

Range clusters 5 and 6: High; similar to

Alternative 4.

Range clusters 1 through 4: Relatively poor.

Cluster 1 — Prediction: Further infestation of dry

grass. The level of further infestation would be

about the same as Alternative 4. Compared with

Alternative 4, the weed control emphasis in Alternative 3 would not be as strong, because only yellow starthistle and dalmatian toadflax would

receive focus for weed control efforts. However,

since the acreages scheduled for weed control are

the same in both alternatives, their level of weed

control would be about the same. In this cluster,

as in Alternative 4, existing infestations would not

likely be reduced in size.

Cluster 2 — Prediction: Further infestation of this

cluster's dry grass, attributable to continued spread of

diffuse knapweed. This prediction was made

because the acreage projected for weed control in

this cluster would be almost negligible (inconsistency; see rangeland assumption 6). Dry grass currently totals approximately 72,000 acres (29,150

ha) on BLM- and FS-administered lands, 95 percent of which is the fescue grassland with conifer

PVT, a PVT that is of high susceptibility to invasion by diffuse knapweed.

Cluster 3 — Prediction: Further infestation of dry

grass. Weed species expected to be the focus of

IWM efforts in this cluster include spotted knapweed, yellow starthistle, leafy spurge, and sulfur

cinquefoil, all of which are highly invasive on dry

grass. The acreage scheduled for weed control in

this cluster is almost negligible (inconsistency; see

rangeland assumption 6); this would lead to continued spread of noxious weeds and infestation of

dry grass, especially the fescue grassland PVTs, at

about the same rate as in Alternative 4.

Landscape Ecology 24?
Table 2.42 — Assumptions about the seven steps of integrated weed management relative to alternative ob

IWM strategy was adapted from Sheley (1994) and used as the foundation for weed management in the p

Description and Use of Seven Steps of Integrated Weed Managem

Step 2 Step3 Step 4 Step 5

Step 1 Prevent Detect and Contain Control 

Emphasis of Inventory and Weed Eradicate New Large-Scale Large-Scale St

Alternative Map Encroachment Introductions Infestations Infestations R

Restore X X X X X 

Conserve X X X X

 2 

Produce X X X X X 

Restore-Produce X X X X X 

Conserve-Restore X X X X X

6

 

Produce-Conserve

7

 X X X X X 

'Revegetation with native species is assumed to be priority, in comparison with the produce emphasis, where revegetation with exotic perennial sp

greater priority. The rationale for using native species is to permit enhancement of floral diversity and also biodiversity. Use of desirable exotic per

native species are not competitive or not available.

2These steps could be implemented, but are not priority for this objective. The rationale is that Steps 5-7 focus on reducing the size and extent o

intent of reclaiming native plant communities, rather than preventing further infestation onto lands not currently infested as is the focus of Steps 

more appropriate for a "conserve" objective.

'Revegetation with exotic perennial species (primarily grasses) may be of greater priority, in comparison with the restore emphasis where revegetati

priority. The rationale for using exotic, perennial species (primarily grasses) is to enhance forage production for livestock and provide aggressive c

native species is expected if objectives can be met.

'Revegetation with native species is assumed to be greater priority, in comparison with exotic, perennial species.

'Proper Range Management is assumed to occur within this emphasis as part of produce. Livestock management practices are assumed to be impl

is less assumed chance of loss of native or exotic revegetated species within this emphasis, compared with the produce emphasis, and consequently 

tate repeatedly to prevent weed reinvasion.

"Steps 5 through 7 of Integrated Weed Management are assumed to be applied for the restore portion of this emphasis.

7

In this emphasis, Steps 1 through 4 of Integrated Weed Management are implemented to conserve. For the produce portion, Steps 5 through 7 a

ious weed-infested sites and permit vegetation production that will sustain livestock.
Table 2.43 — Rank of the effectiveness of alternatives in controlling noxious weeds and cheatgrass in the

dry grass potential vegetation group (Eastside EIS).1

Range Cluster

Rank of Control Effectiveness by Alternative

1

2

3

4

5

6

Overall Rank

0

0

0

1

0

0

0.17

0

0

0

1

0

0

0.17

0.75

0

0

1

2.5

3

1.21

0.75

0

0

1

3

3

1.29

0

0

0

1

0

0

0.17

0.75

0

0

1.5

0.75

3

1

0.5

2

0

1

1.5

2.5

1.25

'0-1 = low effectiveness.

1-2 = moderate effectiveness.

2-3 = high effectiveness.

Ranks should not be compared between clusters, but rather more appropriately within a cluster across alternatives.

Cluster 4 — Prediction: Slow invasion of dry grass

in extent at about the same rate as in Alternative 4.

This prediction is due to both alternatives having

no acreages scheduled for weed control. Weed

species of IWM emphasis in this cluster would be:

leafy spurge, yellow starthistle, and dalmatian

toadflax, all of which are highly invasive on dry

grass. The level of weed control for this cluster for

the entire EEIS area, none under Alternative 3, is

less than that currently being implemented on the

BLM's Spokane District alone.

Cluster 5 — Prediction: Some reclaiming of dry

grass from weeds by year 100. Weed species that

would be a focus of IWM efforts are yellow

starthistle, Mediterranean sage, and dalmatian

toadflax. Of the species listed as problematic on

dry grass in this cluster (appendix 2L, table 2L.5),

yellow starthistle would be the probable target of

most acreage scheduled for weed control.

Although Alternative 3 would be effective in preventing further infestation of dry grass by yellow

starthistle, Mediterranean sage, and dalmatian

toadflax, some further infestation by other species

such as medusahead would likely continue. The

lesser level of livestock management under this

alternative, compared with Alternative 4, would

present increased risk for reinvasion of noxious

weeds, such as yellow starthistle, after treatment.

Cluster 6 — Prediction: Some reclaiming of dry

grass from weeds by year 100. Although the weed

control emphasis under Alternative 3 is not as

strong as in Alternative 4, the acreages scheduled

for weed control treatment under Alternative 3

should be adequate to curtail the spread of problematic noxious weed species in dry grass and to

reclaim some of the dry grass that has been

infested.

Alternative 4 Effectiveness (Dry Grass, EEIS)

Overall rank: 1.29, near the low end of Moderate

effectiveness.

Effectiveness in preventing further infestation of

dry grass:

Range clusters 5 and 6: High

Range clusters 1 through 4: Relatively poor

Cluster 1 — Prediction: Further infestation of dry

grass. Weed species in this cluster receiving IWM

emphasis would be yellow starthistle, dalmatian

toadflax, diffuse knapweed, rush skeletonweed,

medusahead, and whitetop. The IWM emphasis

of Alternative 4 would be to accommodate control (reduction in size) of infestations of these

species and rehabilitation of dry grass. However,

because of this cluster's infestation extent and

Landscape Ecology 249
highly roaded nature, the acreages scheduled for

weed control would only accommodate control of

these species in high-disturbance areas such as

along roads. Spread of existing infestations would

continue.

Cluster 2 — Prediction: Further infestation of dry

grass. Weed species in this cluster receiving IWM

emphasis would include crupina, diffuse knapweed, and tansy ragwort. However, no acreage

would be scheduled for weed control under this

alternative. Of the three species mentioned, diffuse knapweed in particular would continue to

spread and result in further infestation of the

already limited dry grass in this cluster.

Cluster 3 — Prediction: Further infestation of dry

grass. Weed species in this cluster receiving IWM

emphasis would be: whitetop, diffuse knapweed,

spotted knapweed, yellow starthistle, orange and

yellow hawkweeds, leafy spurge, matgrass, sulfur

cinquefoil, tansy ragwort, and rush skeletonweed.

Since Alternative 4 does not schedule acreage in

this cluster for weed control, these species would

continue to spread and infest dry grass, particularly the fescue grassland PVTs.

Cluster 4 — Prediction: Slow invasion of dry grass.

This prediction is due to no acreage being scheduled for weed control under this alternative. Weed

species that would be emphasized by IWM in this

cluster would be whitetop, diffuse knapweed, leafy

spurge, yellow starthistle, rush skeletonweed, and

dalmatian toadflax. The level of weed control projected for this cluster and alternative for the entire

EEIS area, which is none, would be less than

weed control that is currently implemented for

this cluster on the BLM's Spokane District alone.

Clusters 5 and 6 — Prediction: Some reclaiming of

dry grass from weeds by year 100. The acreage

scheduled under the "Improve Rangelands" activity in these clusters is quite high, and should be

adequate to curtail further spread of the weed

species proposed as problematic in dry grass

(appendix 2L, tables 2L.5 and 2L.6). Further

infestation of wheatgrass grassland, fescue grassland, and fescue grassland with conifer PVTs will

be prevented.

Alternative 6 Effectiveness (Dry Grass, EEIS)

Overall rank: 1, at high end of low effectiveness.

Effectiveness in preventing further infestation of

dry grass:

Range cluster 6: High

Range cluster 4: Moderate

Range clusters 1, 2, 3 and 5: Relatively poor

Clusters 1, 2, and 3 — See discussion for these

clusters under Alternative 4.

Cluster 4 — Prediction: Further infestation of dry

grass in this cluster, but to a lesser extent than in

Alternative 4. The IWM emphases of Alternatives

6 and 4 are identical, except there would be more

acreage scheduled for weed control in Alternative

6 (inconsistency; see rangeland assumption 6).

Even with the greater acreage for weed control,

there would be some further infestation of dry

grass.

Cluster 5 — Prediction: Further infestation of dry

grass. The infestations would be attributable to the

relatively low acreage scheduled for weed control,

compared with Alternative 4. Sources of infestation would be diffuse knapweed, yellow starthistle, rush skeletonweed, medusahead, dalmatian

toadflax, and whitetop. Although Alternative 6

would place more emphasis than Alternative 4 on

eradicating new infestations and preventing spread

of species, the acreage scheduled for weed control

under Alternative 6 would not likely prevent further infestation of dry grass.

Cluster 6 — Prediction: Some reclaiming of dry

grass from weeds by year 100. Weed species that

would receive IWM emphasis include yellow

starthistle, Mediterranean sage, diffuse knapweed,

spotted knapweed, dalmatian toadflax, and cheatgrass. The acreage scheduled for weed control is

believed to be relatively high compared with the

acreage of current infestations on dry grass. The

acreage scheduled will permit retreatment of

infestations.

Landscape Ecology
Alternative 7 Effectiveness (Dry Grass, EEIS)

Overall rank: 1.25, at the low end of Moderate

effectiveness; essentially the same as Alternatives 3

and 4.

Effectiveness in preventing further infestation of

dry grass:

Range cluster 6: High

Range clusters 2 and 5: Moderate

Range clusters 1,3, and 4: Relatively Poor

Cluster 1 — Prediction: Further infestation of dry

grass, slightly more than in Alternative 3. There are

approximately 113,000 acres (45,749 ha) of dry

grass on BLM- and FS-administered lands in this

cluster, of which 16 percent or some 18,000 acres

(7,288 ha) is in reserves. The reserves are mostly

in the Lost and Goose Lake subbasins near

Lakeview, Oregon.

Yellow starthistle, medusahead, and possibly leafy

spurge are species that threaten this dry grass in

reserves. Most dry grass on BLM- and FS-administered lands is outside reserves; also, the weed

control scheduled in this cluster and with this

alternative's emphasis is less than in Alternative 3.

Cluster 2 — Prediction: Minor further infestation

of dry grass. There are approximately 200,000

acres (80,972 ha) of dry grass on BLM- and FSadministered lands in this cluster as a whole, of

which 93 percent or approximately 186,000 acres

(75,304 ha) is in reserves. Almost all of the dry

grass on BLM- and FS-administered lands in this

cluster for both EIS areas is in reserves.

Presently, there is only a minor problem with noxious weeds in dry grass in this cluster; allocating

most of the dry grass acreage to reserves should

help prevent spread of noxious weeds, even without any acreage being scheduled for weed control

under this alternative and cluster.

Cluster 3 — Prediction: Further infestation of dry

grass of about the same magnitude as other alternatives. There are approximately 377,600 acres

(152,875 ha) of dry grass on BLM- and FSadministered lands in this cluster as a whole, of

which 46 percent or approximately 175,200 acres

(70,931 ha) is in reserves. Most reserves within

the EEIS area are in the North Fork John Day

and Powder subbasins. The following species are

predicted to be in those reserves, if not there

already: whitetop, yellow starthistle, and Mediterranean sage.

Almost 95 percent of the dry grass in the Eastside

EIS area of this cluster is either the fescue grassland or fescue grassland with conifer PVT.

Although current acreage infestations of diffuse

knapweed, yellow starthistle, whitetop, leafy

spurge, and sulfur cinquefoil are not yet extensive,

these weeds are quite invasive in these grass types.

The acreage scheduled for weed control under

Alternative 7, which is zero, would not slow their

spread.

Cluster 4 — Prediction: Further infestation of dry

grass at about the same level as in Alternative 3.

There are approximately 71,000 acres (28,745 ha)

of dry grass in this cluster on BLM- and FSadministered lands, of which 21 percent or

approximately 15,100 acres (6,113 ha) are in

reserves. This acreage in reserves is predicted to

remain susceptible to weed invasion, even in the

relative absence of disturbance under Alternative

7. The acreage scheduled for weed control is predicted to result in about the same level of weed

control and suppression as in Alternative 3

(inconsistency; see rangeland assumption 6).

Weed species that will further infest dry grass are

diffuse knapweed, whitetop, yellow starthistle,

rush skeletonweed, and dalmatian toadflax.

Cluster 5 — Prediction: Further infestation of dry

grass, but less further infestation than Alternative 6.

The acreage scheduled for weed control is greater

than in Alternative 6. There are approximately

472,000 acres (191,093 ha) of dry grass in

reserves in cluster 5 as a whole, less than half of

which appears to be in the Eastside EIS area (map

2.25). Most dry grass in the EEIS area is located

in the Imnaha subbasin, which has approximately

21,000 acres (8,502 ha) of the wheatgrass grassland PVT, and 86,000 acres (34,818 ha) of the

Landscape Ecology 253,
fescue grassland with conifer PVT. There are only

about 192,000 acres (77,733 ha) of dry grass on

BLM-and FS-administered lands in the EEIS area

of this cluster, which includes 106,000 acres

(42,915 ha) in the Imnaha subbasin, mostly in

reserves. BLM- and FS-administered lands outside

reserves have very little dry grass.

The effectiveness rank of Alternative 7 for this

range cluster should be high, at least outside the

reserves, due to the very low level of dry grass

there and the sufficient acreage scheduled for

weed control outside reserves. In the reserves,

however, there could be a problem with yellow

starthistle. This weed is a problem species in the

dry grass PVG and has known likelihood for

spreading in the wheatgrass grassland PVT, even

without much disturbance.

Cluster 6 — Prediction: Some reclaiming of dry

grass from weeds by year 100. There are approximately 165,100 acres (66,842 ha) of dry grass in

reserves in cluster 6 for both EIS areas, very little

of which appears to be in the Eastside EIS area.

This means that the acreage scheduled for weed

control must be directed essentially to the same

land mass as in Alternative 3. However, Alternative 7 would have substantially less acreage scheduled for weed control than Alternatives 3, 4, and

6, and therefore less reclaiming of dry grass from

weeds compared with those three alternatives.

Dry Grass Potential Vegetation Group

(UCRB)

The effectiveness of the alternatives to prevent

further infestations of the dry grass potential vegetation group in the Upper Columbia River Basin

EIS area is ranked by range cluster and alternative

on table 2.44.

Alternatives 1 and 2 Effectiveness

(Dry Grass, UCRB)

Overall rank: 0, which is low effectiveness.

Effectiveness in preventing further infestation of

dry grass:

Range clusters 2, 3, 5, and 6: Poor

The fragmented manner in which noxious weeds

are controlled in these alternatives at present does

not permit prevention of further infestation of dry

grass by noxious weeds. A point needing resolution is that the substantive acreages scheduled per

decade for weed control in clusters 5 [30,000

acres (12,146 ha)] and 6 [17,500 acres (7,085

ha)] in Alternative 2 may be greater than that

actually being implemented on the ground.

Alternative 3 Effectiveness

(Dry Grass, UCRB)

Overall rank: 1.5, the same as Alternative 4,

which would be Moderate effectiveness.

Effectiveness in preventing further infestation of

dry grass:

Range clusters 5 and 6: High

Range clusters 2 and 3: Poor

Cluster 2 — Prediction: Further infestation of dry

grass by year 100. Although noxious weeds are not

a major problem on dry grass in this cluster, there

would be some infestations attributable to leafy

spurge, spotted knapweed, and yellow starthistle.

The IWM emphasis is not as strong in Alternative

3 compared with Alternative 4, and the acreages

scheduled for weed control and livestock management are nearly negligible (inconsistency; see

rangeland assumption 6). Due to these two factors, weed control efforts under Alternative 3 in

this cluster would not stop the spread of noxious

weeds to non-infested areas, nor reclaim dry grass

that is currently infested.

Cluster 3 — Prediction: Further infestation of dry

grass. This would be attributable particularly to

spotted knapweed, yellow starthistle, leafy spurge,

and sulfur cinquefoil. The IWM emphasis is not

as strong in Alternative 3 as in Alternative 4, and

the acreages scheduled for weed control and livestock management are nearly negligible (inconsistency; see rangeland assumption 6). Weed control

efforts would not stop the spread of noxious

weeds to uninfested areas, nor would they reclaim

dry grass that is currently infested.

252 Landscape Ecology
Map 2.25 - Location of Alternative 7 proposed reserve areas on BLM- and FS-administered lands. Selection of proposed reserve areas was based 

on roadless areas greater than 400 ha (1,000 acres) that were distributed across a range of environments. 

Landscape Ecology 
Table 2.44 — Rank of the effectiveness of alternatives in controlling noxious weeds and cheatgrass in the

dry grass potential vegetation group by range cluster and alternative (Upper Columbia River Basin).1

Range Cluster

Rank of Control Effectiveness by Alternative

2

3

5

6

Overall rank

0

0

0

0

0

0

0

0

0

0

0

0

3

3

1.5

0

0

3

3

1.5

0

0

0

1

0.25

0

0

1.5

3

1.12

0

0

2.5

2.5

1.25

'0-1 = low effectiveness.

1 -2 = moderate effectiveness.

2-3 = high effectiveness.

Ranks should not be compared between clusters, but rather more appropriately within a cluster across alternatives.

Acreages proposed for weed control in this cluster

for all alternatives in dry grass are below that currently being implemented on National Forests in

the UCRB area,4 which points to a flaw in the

activity tables that needs to be resolved.

Cluster 5 — Prediction: Prevention of further infestation of dry grass and, by year 100, some reclaiming

of dry grass that is currently infested with noxious

weeds. Problem species of major concern in this

cluster on dry grass are yellow starthistle, rush

skeletonweed, medusahead, leafy spurge, cheatgrass, and possibly spotted knapweed. Although

Alternative 3 has a weaker IWM emphasis than

Alternative 4, its acreages scheduled for weed control should be adequate to prevent further spread

of noxious weeds, particularly yellow starthistle

and rush skeletonweed. These acreages also should

accommodate reseeding efforts in dry grass areas

that are currently infested with medusahead and

cheatgrass to the point that native species have

been displaced.

Acreages scheduled for livestock management,

although less than Alternative 4, should be adequate to help prevent the spread of noxious weeds

and prevent reinvasion of sites by noxious weeds

after initial weed control.

Cluster 6 — Prediction: Prevention of farther infestation of dry grass and some reclaiming of dry grass

by year 100 that is currently infested with noxious

weeds. Problem species of major concern in this

cluster on dry grass are Dyers woad and leafy

spurge. Although the IWM emphasis of Alternative 3 is weaker compared with Alternative 4,

acreages scheduled for weed control should be

adequate to prevent further spread of noxious

weeds. These acreages also should be suitable to

reseed in the dry grass areas that are currently so

infested with medusahead and cheatgrass that

native species have been displaced. The extent of

dry grass having medusahead and cheatgrass infestations in this cluster is thought to be minor

because there is very little dry grass in the western

portion of the UCRB, where medusahead and

cheatgrass are most prevalent. Further, acreages

scheduled for livestock management should be

adequate to help prevent the spread of noxious

weeds and prevent the reinvasion of sites by noxious weeds after initial weed control.

Alternative 4 Effectiveness

(Dry Grass, UCRB)

Overall rank: 1.5, which is Moderate effectiveness.

4

Personal communication. 1996. Peter M. Rice, Research Associate, Division of Biological Sciences, University of Montana,

Missoula, Montana.

254 Landscape Ecology
Effectiveness in preventing further infestation of

dry grass:

Range clusters 5 and 6: High

Range clusters 2 and 3: Poor

Cluster 2 — Prediction: Further infestation of dry

grass by year 100. Although prevalence of noxious

weeds on dry grass in this cluster is relatively

minor, there would be continued infestation by

leafy spurge, spotted knapweed, and yellow starthistle. Although this alternative would have a

strong IWM emphasis, its acreages scheduled for

weed control and livestock management are nearly

negligible (inconsistency; see rangeland assumption 6). Weed control efforts undertaken in

Alternative 4 would not stop the spread of noxious weeds to non-infested areas, nor reclaim dry

grass that is currently infested in this cluster.

Cluster 3 — Prediction: Further infestation of dry

grass. These infestations would particularly be

attributable to spotted knapweed, yellow starthistle, leafy spurge, and sulfur cinquefoil. Although

Alternative 4 would have a strong IWM emphasis,

its acreages scheduled for weed control and livestock management are nearly negligible (inconsistency; see rangeland assumption 6). Its weed control efforts would not be adequate to stop the

spread of noxious weeds to non-infested areas, or

to reclaim dry grass that is currently infested.

Cluster 5 — Prediction: Prevention of further infestation of dry grass and, by year 100, some reclaiming

of dry grass that is currently infested with noxious

weeds. Problem species of major concern in this

cluster on dry grass are yellow starthistle, rush

skeletonweed, medusahead, leafy spurge, cheatgrass, and possibly spotted knapweed. This alternative would have a strong IWM emphasis and

acreage scheduled for weed control should be adequate to prevent further spread of noxious weeds,

particularly yellow starthistle and rush skeletonweed. In addition, the acreage would be adequate

to do reseeding in dry grass areas currently so

infested with medusahead and cheatgrass that

native species have been displaced. Acreages scheduled for livestock management under Alternative 4

should be adequate to help prevent the spread of

noxious weeds and prevent the reinvasion of sites

by noxious weeds after initial weed control.

Cluster 6 — Prediction: Prevention of further infestation of dry grass and, by year 100, some reclaiming

of dry grass that is currently infested with noxious

weeds. Problem species of major concern in this

cluster on dry grass are Dyers woad and leafy

spurge. The IWM emphasis of Alternative 4 is

strong, and further, the acreages scheduled for

weed control should be adequate to prevent further spread of noxious weeds. These acreages of

weed control also should accommodate reseeding

efforts in dry grass areas currently so infested with

medusahead and cheatgrass that native species

have been displaced. The extent of dry grass having medusahead and cheatgrass infestations in this

cluster is thought to be minor because there is

very little dry grass in the western portion of the

UCRB EIS area, where medusahead and cheatgrass are most prevalent. Acreages scheduled for

livestock management in Alternative 4 should be

adequate to help prevent the spread of noxious

weeds and prevent the reinvasion of sites by noxious weeds after initial weed control.

Alternative 5 Effectiveness

(Dry Grass, UCRB)

Overall rank: 0.25, which is Low effectiveness.

Effectiveness in preventing further infestation of

dry grass:

Range clusters 2, 3, 5, and 6: Poor

Cluster 2 — Prediction: Further infestation of dry

grass by year 100. Although prevalence of noxious

weeds on dry grass in this cluster is relatively

minor, there would be continued infestation by

leafy spurge, spotted knapweed, and yellow starthistle. The IWM emphasis of Alternative 5

would be the same as Alternative 3, but the

acreages scheduled for weed control and livestock

management would be even less than Alternative

3 (inconsistency; see rangeland assumption 6).

Weed control efforts would not stop the spread of

noxious weeds to non-infested areas, nor reclaim

dry grass that is currently infested.

Landscape Ecology 255
Cluster 3 — Prediction: Further infestation of dry

grass. Further infestation would be particularly

attributable to spotted knapweed, yellow starthistle, leafy spurge, and sulfur cinquefoil. Alternatives 5 and 3 would have the same level of IWM

emphasis, except the acreages scheduled for weed

control and livestock management would be less

for Alternative 5 (inconsistency; see rangeland

assumption 6). This level of emphasis would not

stop the spread of noxious weeds to non-infested

areas, nor reclaim dry grass that is currently

infested.

Cluster 5 — Prediction: Further infestation of dry

grass. Noxious weed species in this cluster that are

prevalent on dry grass include yellow starthistle,

rush skeletonweed, medusahead, leafy spurge,

cheatgrass, and possibly spotted knapweed.

Although this alternatives IWM emphasis is

stronger than Alternative 3 for this cluster, the

acreages projected for weed control would be

inadequate to prevent spread of noxious weeds.

Compared with Alternative 3, the acreages scheduled for livestock management under Alternative

5 would be much lower, which would offer only

limited effectiveness in preventing the spread of

noxious weeds and preventing reinvasion of sites

by noxious weeds after initial weed control.

Cluster 6 — Prediction: Further infestation of dry

grass not currently infested with noxious weeds.

Noxious weed species in this cluster that are

prevalent on dry grass are Dyers woad and leafy

spurge. Although this alternative's IWM emphasis

is the same as Alternative 3, the acreages scheduled for weed control and livestock management

under Alternative 5 would permit further infestation of dry grass. The acreage also would not be

sufficient to permit reseeding of areas having dry

grass dominated by cheatgrass and medusahead.

Alternative 6 Effectiveness

(Dry Grass, UCRB)

Overall rank: 1.12, which is at the low end of

Moderate effectiveness.

Effectiveness in preventing further infestation of

dry grass:

Range cluster 6: High

Range cluster 5: Moderate

Range clusters 2 and 3: Poor

Cluster 2 — Prediction: Further infestation of dry

grass is predicted by year 100. Although the prevalence of noxious weeds on dry grass in this cluster

is relatively minor, there would be continued infestations attributable to leafy spurge, spotted knapweed, and yellow starthistle. Although Alternative

6 places a strong emphasis on weed management at

essentially the same level as Alternative 4, its

acreages scheduled for weed control and livestock

management are nearly negligible (inconsistency;

see rangeland assumption 6). The weed control

efforts of Alternative 6 would not stop the spread

of noxious weeds to non-infested areas, nor reclaim

dry grass that is currently infested in this cluster.

Cluster 3 — Prediction: Further infestation of dry

grass. Further infestation would be attributable

particularly to spotted knapweed, yellow starthistle, leafy spurge, and sulfur cinquefoil.

Although this alternative would have stronger

IWM emphasis in this cluster than Alternative 4,

its acreages scheduled for weed control and livestock management are nearly negligible. Weed

control efforts would not stop the spread of noxious weeds to non-infested areas nor reclaim dry

grass that is currently infested.

Cluster 5 — Prediction: Further infestation of dry

grass. Further infestation would be attributable

particularly to yellow starthistle, rush skeletonweed, medusahead, leafy spurge, cheatgrass, and

possibly spotted knapweed. Although the Alternative 6 IWM emphasis in this cluster actually

would be stronger than in Alternative 4, its

acreage scheduled for weed control would be onethird that of Alternative 4. This acreage would

still permit some further spread of noxious weeds

into previously non-infested dry grass. The

acreages scheduled for livestock management,

which would be the same as in Alternative 4,

should help prevent the spread of noxious weeds

and prevent the reinvasion of sites by noxious

weeds after initial weed control.

Landscape Ecology
Cluster 6 — Prediction: Prevention of further infestation of dry grass and, by year 100, some reclaiming

of dry grass that is currently infested with noxious

weeds. Noxious weed species that are particularly

prevalent in this cluster on dry grass are Dyers

woad and leafy spurge. The IWM emphasis of

Alternative 6 in this cluster would be just as

strong as that of Alternative 4. Although acreages

scheduled for weed control in Alternative 6 would

be lower, they would still be adequate to prevent

further spread of noxious weeds. This acreage

should also accommodate reseeding efforts in dry

grass areas currently so infested with medusahead

and cheatgrass that native species have been displaced. The extent of dry grass having medusahead and cheatgrass infestations in this cluster is

thought to be minor because there is very little

dry grass in this cluster in the western portion of

the UCRB EIS area, where medusahead and

cheatgrass are most prevalent.

The acreages scheduled for livestock management

under Alternative 6 should be adequate to help

prevent the spread of noxious weeds and prevent

reinvasion of sites by noxious weeds after initial

weed control.

Alternative 7 Effectiveness

(Dry Grass, UCRB)

Overall rank: 1.25, at the low end of Moderate

effectiveness.

Effectiveness in preventing further infestation of

dry grass:

Range clusters 5 and 6: High

Range clusters 2 and 3: Poor

Cluster 2 — Prediction: Further infestation of dry

grass by year 100. Although prevalence of noxious

weeds on dry grass in this cluster is relatively

minor, there would be continued infestation by

leafy spurge, spotted knapweed, and yellow starthistle. The IWM emphasis of this alternative

would be less than Alternative 4, and acreages

scheduled for weed control and livestock management are nearly negligible (inconsistency; see

rangeland assumption 6). Weed control efforts in

this cluster under Alternative 7 would not stop

the spread of noxious weeds to non-infested areas

nor reclaim dry grass that is currently infested.

Cluster 3 — Prediction: Further infestation of dry

grass. Further infestation would be attributable

particularly to spotted knapweed, yellow starthistle, leafy spurge, and sulfur cinquefoil. The IWM

emphasis of Alternative 7 in this cluster is not as

strong as Alternative 4, and the acreages scheduled

for weed control and livestock management are

nearly negligible (inconsistency; see rangeland

assumption 6). Weed control efforts would not

stop the spread of noxious weeds to non-infested

areas nor reclaim dry grass currently infested.

Cluster 5 — Prediction: Some reclaiming of dry

grass from weeds by year 100. The IWM emphasis

of Alternative 7 would be the same as Alternative

3, but its acreages scheduled for weed control

would be lower. With this emphasis and acreage

level, further infestation of dry grass would be

prevented outside reserves, but minor further

infestation of dry grass would occur within

reserves. Further, although acreages scheduled for

livestock management would be lower than for

Alternative 3, they should be adequate to help

prevent the spread of noxious weeds and prevent

the reinvasion of sites by noxious weeds after initial weed control.

Cluster 6 — Prediction: Some reclaiming of dry

grass from weeds by year 100. Because areas outside

of reserves have the same IWM emphasis as

Alternative 3, comparing these two alternatives is

useful. The acreages scheduled for weed control

will not accommodate reseeding efforts in dry

grass and for this reason there will be less net gain

in dry grass compared with Alternative 3.

Acreages scheduled for livestock management

should be adequate to help prevent the spread of

noxious weeds and prevent the reinvasion of sites

by noxious weeds after initial weed control.

There is concern, however, that the lack of control

efforts in reserves would permit the establishment

and spread of leafy spurge and Dyers woad, and

perhaps other noxious weeds such as spotted

knapweed, in the dry grass PVG (comprised

Landscape Ecology 25?
mostly of the fescue grassland with conifer PVT

in the Big Wood subbasin).

Dry Shrub Potential Vegetation Group

(EEIS)

The effectiveness of the alternatives to prevent

further infestations of the dry shrub potential vegetation group in the Eastside EIS area is ranked by

range cluster and alternative in table 2.45.

Alternatives 1 and 2 Effectiveness

(Dry Shrub, EEIS)

Overall rank: 0.25, which is Low.

Effectiveness in preventing further infestation of

dry shrub:

Range cluster 4: Moderate

Range clusters 1-3, 5, and 6: Poor

A continuation of the present fragmented manner

of noxious weed control in these alternatives

would not permit prevention of further infestation of dry shrub by noxious weeds. A point needing resolution is that the substantive areas scheduled per decade for weed control in clusters 5

[45,000 acres (18,219 ha)] and 6 [112,500 acres

(45,547 ha)] in Alternative 2 may exceed that

actually being implemented by the BLM and FS

currently.

Cluster 4 — Prediction: Some further infestation of

dry shrub, but at a slower rate than other clusters.

The amounts scheduled for weed control in this

cluster under Alternatives 1 and 2 would be similar to current implementation levels on the BLM's

Spokane District in Washington, where weed

spread is not rampant at this time. In this cluster,

there would be concern with the prevalence of

cheatgrass in the understory of dry shrub and its

strong propensity to dominate after wildfires.

Alternative 3 Effectiveness

(Dry Shrub, EEIS)

Overall rank: 1.83, at the upper end of Moderate.

Effectiveness in preventing further infestation of

dry shrub:

Range clusters 5 and 6: High

Range clusters 1, 2, and 4: Moderate

Range cluster 3: Poor

Cluster 1 — Prediction: Minor further infestation

of dry shrub. Noxious weeds with prevalence on

dry shrub in this cluster are diffuse knapweed,

medusahead, and dalmatian toadflax. Weeds of

lesser extent are yellow starthistle, whitetop,

halogeton, and rush skeletonweed. The IWM

emphasis of this alternative would not be as

strong in this cluster as in Alternatives 4 and 6.

Table 2.45 — Rank of the effectiveness of alternatives in controlling noxious weeds and cheatgrass in the

dry shrub potential vegetation group by range cluster and alternative (Eastside EIS).'

Range Cluster

Rank of Control Effectiveness by Alternative

1

2

3

4

5

6

Overall rank

0

0

0

1.5

0

0

0.25

0

0

0

1.5

0

0

0.25

2

2

0

2

2.5

2.5

1.83

2.25

2.75

0.5

2

2.75

3

2.21

0.75

2

0.5

2

1.5

2.5

1.54

2.25

2

0.5

2

2

2.75

1.92

0.5

1.5

0

1

1.5

1

0.92

'0-1 = low effectiveness.

1-2 = moderate effectiveness.

2-3 = high effectiveness.

Ranks should not be compared between clusters, but rather more appropriately within a cluster across alternatives.

Landscape Ecology
The acreage scheduled for weed control would be

targeted specifically to diffuse knapweed and

halogeton, because dry shrub is of high susceptibility to invasion by these species. The amount of

acreage should be adequate to control (reduce

infestation size) diffuse knapweed and halogeton,

and permit some control of the other species.

Alternative 3 would not, however, emphasize containment and prevention of spread of noxious

weeds in this cluster.

Cluster 2 — Prediction: Minor further infestation

of dry shrub. Of the dry shrub in this cluster on

BLM- and FS-administered lands, 92 percent is

the antelope bitterbrush PVT. The antelope bitterbrush PVT is of high susceptibility to invasion

by diffuse knapweed, the major noxious weed in

this cluster that threatens dry shrub. The IWM

emphasis of this alternative in this cluster would

be less than Alternative 4. The limited acreage

scheduled for weed control (inconsistency; see

rangeland assumption 6) would specifically target

diffuse knapweed but would likely be inadequate

to totally prevent spread of this species and further infestation.

Cluster 3 — Prediction: Further infestation of dry

shrub. Noxious weeds with prevalence in dry

shrub in this cluster are whitetop and possibly yellow starthistle. Others, such as diffuse knapweed,

squarrose knapweed, and rush skeletonweed, are

less extensive at present; in the future, however,

they could become prevalent weeds in dry shrub

in this cluster. The IWM emphasis of this alternative would be less than Alternatives 4 and 6,

attributable in part to less acreage being scheduled

for weed control. The level of weed control would

not be adequate to prevent further spread of noxious weeds into dry shrub, especially whitetop.

Although diffuse knapweed is quite extensive in

this cluster, its distribution overlaps very little

with the distribution of dry shrub within the

cluster.

Cluster 4 — Prediction: Minor further infestation

of dry shrub, at about the same level as in Alternative 4. Noxious weeds within dry shrub in this

cluster are diffuse knapweed, Russian knapweed,

dalmatian toadflax, cheatgrass, and potentially yellow starthistle. The IWM emphasis of Alternative

3 would not be as strong in this cluster as in

Alternatives 4 and 6. Of the weeds listed, cheatgrass would be the major target of IWM efforts

because dry shrub is of high susceptibility to invasion by cheatgrass. The acreage scheduled for

weed control would be applied to the other weeds

listed with somewhat lesser priority.

The acreage scheduled for weed control in

Alternative 3 would be the same as in Alternatives

4 and 6, and even with this level of weed management, further infestation of dry shrub is predicted, particularly by diffuse knapweed.

Cluster 5 — Prediction: Prevention of further infestation of dry shrub and some reclaiming of dry shrub

from weeds by year 100. Noxious weeds with

prevalence in dry shrub in this cluster include diffuse knapweed, medusahead, halogeton, cheatgrass, and possibly rush skeletonweed. Of these,

halogeton and cheatgrass likely infest the most

land in dry shrub, with halogeton now being

especially prevalent in the Alvord Lake subbasin.

The IWM emphasis of this alternative would not

be as strong in this cluster compared with Alternatives 4 and 6. Further, of the five species mentioned as problematic in this cluster, only halogeton and cheatgrass would actually be the target of

weed control efforts. However, the acreage scheduled is great enough to permit weed control

efforts to be directed to the other species as well.

There would be concern about the extensive

acreages on Other (non-BLM/FS) lands that are

currently infested with diffuse knapweed in the

central Washington portion of this cluster. We

assume control of diffuse knapweed would be

undertaken on these lands, and weed control

efforts would be coordinated so that diffuse

knapweed invasion and spread on BLM- and FSadministered lands can be prevented or slowed.

Cluster 6 — Prediction: Prevention of further infestation of dry shrub and some reclaiming of dry shrub

from weeds by year 100. Noxious weeds with

prevalence in dry shrub in this cluster include

halogeton, medusahead, Mediterranean sage,

Landscape Ecology
cheatgrass, and possibly dalmatian toadflax and

rush skeletonweed. Cheatgrass, medusahead, and

Mediterranean sage are assumed to contribute the

majority of weed acreage in dry shrub.

The IWM control emphasis of Alternative 3

would not be as strong as that in Alternatives 4 or

6. Of the six problematic species, cheatgrass,

Mediterranean sage, and halogeton would be a

priority for weed control. Although acreages

scheduled for weed control in this cluster would

be suitable to effectively prevent spread of the priority species and to control their infestation size as

well, species such as medusahead could continue

to spread. No acreage would be scheduled for prescribed fire activity in Alternative 3, which would

aid in preventing further spread of these weed

species.

Alternative 4 Effectiveness

(Dry Shrub, EEIS)

Overall rank: 2.21, at the low end of High

effectiveness.

Effectiveness in preventing further infestation of

dry shrub:

Range clusters 1, 2, 5 and 6: High

Range cluster 4: Moderate

Range cluster 3: Poor

Cluster 1 — Prediction: Prevention of further infestation of dry shrub and some reclaiming of dry shrub

from weeds by year 100. Noxious weeds with

prevalence on dry shrub in this cluster are diffuse

knapweed, medusahead, and dalmatian toadflax.

Weeds of lesser extent are yellow starthistle, whitetop, halogeton, and rush skeletonweed. The IWM

emphasis under this alternative would be strong in

this cluster, with the acreage scheduled for weed

control being directed mostly to control (reduction in infestation size) and rehabilitation of

infested areas after initial weed control.

Cluster 2 — Prediction: Prevention of further infestation of dry shrub and some reclaiming of dry shrub

from weeds by year 100. Of the dry shrub in this

cluster on BLM- and FS-administered lands, 92

percent is the antelope bitterbrush PVT. The antelope bitterbrush PVT is of high susceptibility to

invasion by diffuse knapweed, the major noxious

weed in this cluster that threatens dry shrub.

Considering the strong IWM emphasis of

Alternative 4 and the acreage scheduled for weed

control, some control of diffuse knapweed in this

cluster would be predicted.

Cluster 3 — Prediction: Further infestation of dry

shrub. Noxious weeds with prevalence in dry

shrub in this cluster are whitetop and possibly yellow starthistle. Others, such as diffuse knapweed,

squarrose knapweed, and rush skeletonweed, are

less extensive at present but could be prevalent

weeds in dry shrub in this cluster in the future.

Although the emphasis of this alternative would

be strong in regard to IWM, the acreage scheduled for weed control would not be adequate to

prevent further spread of noxious weeds onto dry

shrub, particularly whitetop. Although diffuse

knapweed is quite extensive in this cluster, its distribution overlaps very little with the distribution

of dry shrub within the cluster.

Cluster 4 — Prediction: Minor further infestation

of dry shrub. Noxious weeds with prevalence in

dry shrub in this cluster are diffuse knapweed,

Russian knapweed, dalmatian toadflax, cheatgrass,

and potentially yellow starthistle. The IWM

emphasis of this alternative would be strong in

this cluster, with all five problem weeds being the

target of weed control efforts. However, the

acreage scheduled for weed control would not prevent further infestation of dry shrub, particularly

by diffuse knapweed.

Cluster 5 — Prediction: Prevention of further infestation of dry shrub, some reclaiming of dry shrub

from weed by year 100. Noxious weeds with

prevalence in dry shrub in this cluster include

diffuse knapweed, medusahead, halogeton, cheatgrass, and possibly rush skeletonweed. Of these

five, halogeton and cheatgrass likely infest the

most extensive land area in dry shrub, with

halogeton particularly being a problem in the

Alvord Lake subbasin. The IWM emphasis of

Landscape Ecology
Alternative 4 would be strong in this cluster, with

all species mentioned above being prioritized for

weed control efforts. Of concern would be the

extensive acreages of dry shrub on Other lands

that are currently infested with diffuse knapweed

in the central Washington portion of this cluster.

We assume control of diffuse knapweed would be

undertaken on Other lands and efforts would be

coordinated to prevent or slow the invasion and

spread of diffuse knapweed onto BLM- and FSadministered lands.

Cluster 6 — Prediction: Prevention of further infestation of dry shrub and some reclaiming of dry shrub

from weeds by year 100. Noxious weeds with

prevalence in dry shrub in this cluster include

halogeton, medusahead, Mediterranean sage,

cheatgrass, and possibly dalmatian toadflax and

rush skeletonweed. The majority of weed acreage

in dry shrub is contributed by three of these six

species: cheatgrass, medusahead, and Mediterranean sage. Alternative 4 has a strong IWM

emphasis in this cluster. The acreages scheduled

for weed control will prevent further infestation of

dry shrub and also permit reseeding efforts, with

emphasis on native species, on lands dominated

by these noxious weeds. There would be no prescribed fire, which would aid in preventing further spread of these weed species, scheduled.

Alternative 5 Effectiveness

(Dry Shrub, EEIS)

Overall rank: 1.54, which is Moderate.

Effectiveness in preventing further infestation of

dry shrub:

Range cluster 6: High

Range clusters 2, 4, and 5: Moderate

Range clusters 1 and 3: Poor

Cluster 1 — Prediction: Further infestation of dry

shrub. Noxious weeds with prevalence on dry

shrub in this cluster are diffuse knapweed,

medusahead, and dalmatian toadflax; weeds of

lesser extent are yellow starthistle, whitetop,

halogeton, and rush skeletonweed. The IWM

emphasis in Alternatives 5 and 3 would be the

same, but Alternative 5 would schedule much less

acreage. The acreage would specifically target diffuse knapweed and halogeton.

Cluster 2 — See discussion for this cluster under

Alternative 3.

Cluster 3 — Prediction: Further infestation of dry

shrub, at the same Level as in Alternative 4. Noxious

weeds with prevalence in dry shrub in this cluster

are whitetop and, possibly, yellow starthistle.

Others, such as diffuse knapweed, squarrose knapweed, and rush skeletonweed, are less extensive at

present but could become prevalent on dry shrub

in this cluster in the future. Although diffuse

knapweed is quite extensive in this cluster, its distribution overlaps very little with dry shrub within

the cluster.

Although the acreage scheduled for control would

be the same as Alternative 4, the IWM emphasis

of Alternative 5 would not be as strong. This level

of control would not be adequate to prevent further spread of noxious weeds into dry shrub, particularly by whitetop.

Cluster 4 — See discussion for this cluster under

Alternative 3.

Cluster 5 — Prediction: Further infestation of dry

shrub. Noxious weeds with prevalence on dry

shrub in this cluster include diffuse knapweed,

medusahead, halogeton (particularly in the Alvord

Lake subbasin), cheatgrass, and possibly rush

skeletonweed. Of these, halogeton and cheatgrass

are proposed to cover the most extensive land in

dry shrub. Although the IWM emphasis of

Alternative 5 in this cluster would be stronger

than under Alternative 3, the acreage scheduled

would be much less and would actually target

only halogeton. The acreage scheduled, however,

is great enough that some weed control efforts

would be directed to the other species as well, but

not to the extent of Alternative 3.

There would be concern with the extensive

acreages of dry shrub on Other lands that are currently infested with diffuse knapweed in the cenLandscape Ecology 261
tral Washington portion of this cluster. We

assume control of diffuse knapweed would be

done on Other lands and coordinated to prevent

diffuse knapweed from invading and spreading

onto BLM- and FS-administered lands.

Cluster 6 — Prediction: Nearly the same as for this

cluster in Alternative 3, except for the slight difference that very minor acreage would be scheduled

under Alternative 5 for prescribed burning.

Alternative 6 Effectiveness

(Dry Shrub, EEIS)

Overall rank: 1.92, at the high end of Moderate

effectiveness.

Effectiveness in preventing further infestation of

dry shrub:

Range clusters 1 and 6: High

Range clusters 2, 4, and 5: Moderate

Range cluster 3: Poor

Cluster 1 — See discussion for this cluster under

Alternative 4.

Cluster 2 — Prediction: Minor further infestation

of dry shrub. Of dry shrub in this cluster on BLMand FS-administered lands, 92 percent is the antelope bitterbrush PVT. The antelope bitterbrush

PVT is of high susceptibility to invasion by diffuse knapweed, the major noxious weed in this

cluster that threatens dry shrub. Alternative 6 in

this cluster would have the same IWM emphasis

as Alternative 4, but only half the acreage (inconsistency; see rangeland assumption 6).

Cluster 3 — Prediction: Further infestation of dry

shrub, at the same level as Alternative 4. Noxious

weeds with prevalence in dry shrub in this cluster

are whitetop and, possibly, yellow starthistle.

Others, such as diffuse knapweed, squarrose knapweed, and rush skeletonweed, are less extensive at

present but could be prevalent in dry shrub in the

future. Diffuse knapweed is quite extensive in this

cluster, but its distribution overlaps very little with

the distribution of dry shrub within the cluster.

Although Alternative 6 would have a stronger

IWM emphasis than Alternative 4 and the same

acreage scheduled, Alternative 6 would not be

adequate to prevent further spread of noxious

weeds into dry shrub, particularly by whitetop.

Cluster 4 — See discussion for this cluster under

Alternative 4.

Cluster 5 — Prediction: Minor further infestation

of dry shrub. Noxious weeds with prevalence in

dry shrub in this cluster include diffuse knapweed, medusahead, halogeton (particularly in the

Alvord Lake subbasin), cheatgrass, and possibly

rush skeletonweed. Of these, halogeton and cheatgrass are proposed to cover the most extensive

land in dry shrub.

The IWM emphasis of this alternative would

actually be stronger in this cluster compared with

Alternative 4, and all weeds mentioned above

would be prioritized for weed control efforts.

Under Alternative 6, however, only one-third of

the acreage as Alternative 4 would be scheduled

for weed control. There would also be concern

with the extensive acreages of dry shrub on Other

lands that are currently infested with diffuse knapweed in the central Washington portion of this

cluster. We assume control of diffuse knapweed

would be undertaken on Other lands and efforts

be coordinated to prevent invasion and spread of

diffuse knapweed onto BLM- and FS-administered lands.

Cluster 6 — Prediction: Prevention of further infestation of dry shrub and some reclaiming of dry shrub

from weeds by year 100. Noxious weeds with prevalence in dry shrub in this cluster include halogeton, medusahead, Mediterranean sage, cheatgrass,

and possibly dalmatian toadflax and rush skeletonweed. The majority of weed acreage in dry shrub is

contributed by three of these species: cheatgrass,

medusahead, and Mediterranean sage.

The IWM emphasis of Alternative 6 in this cluster would be strong, the same as Alternative 4.

The acreages scheduled for weed control under

Alternative 6 should be adequate to prevent further infestation of dry shrub, and to permit

262 Landscape Ecology
reseeding efforts, giving emphasis to native

species, on lands dominated by these noxious

weeds. Further, no acreage would be scheduled for

prescribed fire, which would aid in preventing

further spread of these weed species.

Alternative 7 Effectiveness

(Dry Shrub, EEIS)

Overall rank: 0.92, at the high end of Low

effectiveness.

Effectiveness in preventing further infestation of

dry shrub:

Range clusters 2 and 5: Moderate

Range clusters 1, 3, 4, and 6: Poor

Cluster 1 — Prediction: Further infestation of dry

shrub, in reserves and outside reserves. There are

only approximately 41,000 acres (16,599 ha) of

dry shrub in this cluster within reserves, with

most of it located in the Lost and Goose Lake

subbasins within BLM's Lakeview District in

southeast Oregon. Medusahead and yellow starthistle are prevalent in these subbasins (4th-field

HUCs) and are predicted to continue spreading

into dry shrub in reserves. This continued spread

would not be attributable to livestock grazing, but

perhaps to fire opening up microsites for establishment. The acreage scheduled for weed control

outside reserves would not be adequate to prevent

spread of diffuse knapweed and other noxious

weeds.

Cluster 2 — Prediction: Some further infestation of

dry shrub. Of dry shrub in this cluster on BLMand FS-administered lands, 92 percent is the antelope bitterbrush PVT. The antelope bitterbrush

PVT is of high susceptibility to invasion by diffuse knapweed, the major noxious weed in this

cluster that threatens dry shrub. The IWM

emphasis of this alternative outside of the reserves

would be the same as Alternative 3; however,

within reserves in north-central Washington,

where some dry shrub appears to be located, diffuse knapweed would invade and would not be

controlled.

Cluster 3 — Prediction: Further infestation of dry

shrub. Noxious weeds with prevalence in dry

shrub in this cluster are whitetop and possibly yellow starthistle. Others, such as diffuse knapweed,

squarrose knapweed, and rush skeletonweed, are

less extensive at present but could become prevalent in dry shrub in the future. The IWM emphasis of this alternative outside of the reserves would

be the same as Alternative 3. Because Alternative

7 would not schedule weed control in reserves,

there would be concern in the Powder subbasin.

Most of the dry shrub in reserves is located in the

Powder subbasin (4th-field HUC), where whitetop is present currently and is possibly already

infesting dry shrub. The acreage scheduled for

weed control will not prevent the spread of noxious weeds. Diffuse knapweed is quite extensive in

this cluster, but its distribution in the cluster overlaps very little with the distribution of the dry

shrub.

Cluster 4 — Prediction: Further infestation of dry

shrub, particularly in dry shrub in reserves. Noxious

weeds with prevalence in dry shrub in this cluster

are diffuse knapweed, Russian knapweed, dalmatian toadflax, cheatgrass, and potentially yellow

starthistle. The IWM emphasis of this alternative

outside reserves would be the same as Alternative

3. Of the weeds listed, cheatgrass would be the

major target of IWM efforts because dry shrub is

of high susceptibility to invasion by cheatgrass.

The acreage scheduled for weed control, which is

the same as for Alternatives 4 and 6, would be

directed to the other weeds listed too, but in somewhat lesser priority compared with cheatgrass.

Outside reserves, it is predicted that further infestation of dry shrub by these weeds would be prevented. In reserves in this cluster, however, where

50 percent of the dry shrub on BLM- and FSadministered lands is located, further infestation

of dry shrub is predicted. This prediction is based

on the reserves being so fragmented and often surrounded by Other lands.

Cluster 5 — Prediction: Further infestation of dry

shrub, at about the same level as Alternative 5.

Noxious weeds with prevalence in dry shrub in

Landscape Ecology 263
this cluster include diffuse knapweed, medusahead, halogeton (particularly in the Alvord Lake

subbasin), cheatgrass, and possibly rush skeletonweed. Of these, halogeton and cheatgrass are proposed to be the most extensive in land coverage in

dry shrub. The IWM emphasis of this alternative

outside of reserves would be the same as Alternative 3; however, of the species mentioned, only

halogeton would actually be targeted outside

reserves. The dry shrub within reserves is mostly

found within the Upper Quinn, Middle Owyhee,

and East Little Owyhee subbasins, where currently noxious weeds are not prevalent and cheatgrass

is not dominant.

The acreage scheduled for weed control would

permit further infestation of dry shrub by diffuse

knapweed and medusahead. This prediction is of

concern in the central Washington portion of this

cluster, where extensive acreages of dry shrub on

Other lands are currently infested with diffuse

knapweed. We assume control of diffuse knapweed would be undertaken on Other lands, but

diffuse knapweed from Other lands is still predicted to spread into dry shrub in the vicinity, of

which some is in reserves.

Cluster 6 — Prediction: Further infestation of dry

shrub. Comparing dry shrub in and outside

reserves, the prediction is for relatively more rapid

infestation of dry shrub in reserves. Noxious

weeds with prevalence in dry shrub in this cluster

include halogeton, medusahead, Mediterranean

sage, cheatgrass, and possibly dalmatian toadflax

and rush skeletonweed. It is assumed that the

majority of weed acreage in dry shrub is contributed by cheatgrass, medusahead, and

Mediterranean sage. The IWM emphasis of this

alternative would be the same as Alternative 3,

but only outside reserves. Additionally, only half

of the problem species listed above would be targeted by IWM; these would include cheatgrass,

Mediterranean sage, and halogeton.

In this cluster, there would be concern that the

acreages scheduled for weed control would be

inadequate to effectively prevent spread of the targeted species, or to control their infestation size.

The dry shrub in reserves is located mostly in the

Warner Lakes and Guano subbasins, which already

have weed infestations, particularly Mediterranean

sage and medusahead. These species are predicted

to continue spreading in reserves.

Dry Shrub Potential Vegetation Group

(UCRB)

The effectiveness of the alternatives to prevent

further infestations of the dry shrub potential vegetation group in the Upper Columbia River Basin

EIS area is ranked by range cluster and alternative

in table 2.46.

Alternatives 1 and 2 Effectiveness

(Dry Shrub, UCRB)

Overall rank: 1.5, which is Moderate.

Effectiveness in preventing further infestation of

dry shrub:

Range clusters 2 and 3: High

Range clusters 5 and 6: Poor

The high effectiveness in clusters 2 and 3 was

based on the assumption that the acreage scheduled for weed control for these alternatives would

be implemented, and also on the presence of very

little dry shrub in these two clusters.

The poor rating in clusters 5 and 6 is primarily

related to the fragmented manner of noxious weed

control proposed in these alternatives which

would not prevent further infestation. In particular to Alternative 2, a point needing resolution is

the substantive acreages scheduled per decade for

weed control in these two clusters; the 130,000

acres (52,632 ha) in cluster 5 and 77,500 acres

(31,377 ha) in cluster 6 may exceed actual

acreages being implemented on the ground.

Alternative 3 Effectiveness

(Dry Shrub, UCRB)

Overall rank: 2.5, which is High.

Effectiveness in preventing further infestation of

dry shrub:

264 Landscape Ecology
Table 2.46 — Rank of the effectiveness of alternatives in controlling noxious weeds and cheatgrass in the

dry shrub potential vegetation group by range cluster and alternative (Upper Columbia River Basin).'

Range Cluster

Range of Control Effectiveness by Alternative

2

3

5

6

Overall rank

3

3

0

0

1.5

3

3

0

0

1.5

3

3

2.5

1.5

2.5

3

3

3

2

2.75

3

3

1

0.75

1.94

3

3

1.5

1.25

2.19

2

3

0.5

1

1.62

'0-1 = low effectiveness.

1-2 = moderate effectiveness.

2-3 = high effectiveness.

Ranks should not be compared between clusters, but rather more appropriately within a cluster across alternatives.

Range clusters 2, 3, and 5: High

Range cluster 6: Moderate

Clusters 2 and 3 — See discussion for these clusters under Alternative 4.

Cluster 5 — Prediction: Prevention of further infestation of dry shrub and some reclaiming of dry shrub

from weeds by year 100. Noxious weeds with

prevalence in dry shrub in this cluster are yellow

starthistle, rush skeletonweed, medusahead,

halogeton, and cheatgrass. Compared with Alternative 4, the IWM emphasis of this alternative

would not be as strong. Cheatgrass and halogeton

will be the species targeted for IWM efforts.

However, the acreage scheduled for weed control

is predicted to be adequate to permit some weed

control of the other species as well. Further, weed

control efforts will result in reseeding and rehabilitation of some areas currently dominated by

cheatgrass and/or medusahead and other noxious

weeds. The emphasis of Alternative 3 in this cluster would be on control (reduction in infestation

size), and rehabilitation. The acreage scheduled

for "Livestock Management" would be about half

that of Alternative 4, which could result in a relatively greater failure rate for seedings and a relatively greater risk of spreading weeds into currently uninfested areas.

Cluster 6 — Prediction: Some further infestation of

dry shrub. Noxious weeds with prevalence in dry

shrub in this cluster are Dyers woad, diffuse knapweed, yellow starthistle, medusahead, rush skeletonweed, and cheatgrass. The IWM emphasis of

this alternative would not be as strong in this cluster as in Alternative 4. Also, weed control efforts

would specifically target cheatgrass and Dyers

woad, resulting in some further infestation of dry

shrub by other species. Not emphasizing steps 1

through 4 of IWM would result in lower emphasis on greenstripping, a technique used to prevent

further spread of annual grasses into native shrubsteppe vegetation (dry shrub). However, there

would be focus in this cluster on reseeding of

burned areas that are either presently dominated,

or expected to be dominated, by cheatgrass and/or

medusahead.

Alternative 4 Effectiveness

(Dry Shrub, UCRB)

Overall rank: 2.75, at the high end of High

effectiveness.

Effectiveness in preventing further infestation of

dry shrub:

Range clusters 2, 3, and 5: High

Range cluster 6: Moderate

Cluster 2 — Prediction: Prevention of further infestation of dry shrub and some reclaiming of dry shrub

from weeds by year 100. Noxious weeds of some

Landscape Ecology 265
extent in dry shrub are possibly Mediterranean

sage. Within this cluster, there are only approximately 10,000 acres (4,049 ha) of dry shrub on

BLM- and FS-administered lands, all of which is

the big sagebrush-cool PVT. The acreage scheduled for weed control under Alternative 4 (inconsistency; see rangeland assumption 6) would

accommodate control of the weed acreage currently present on this dry shrub.

Cluster 3 — Prediction: Prevention of further infestation of dry shrub and some reclaiming of dry shrub

from weeds by year 100. Noxious weeds of some

extent in dry shrub are possibly Mediterranean

sage and leafy spurge. Within this cluster, there

are only approximately 3,500 acres (1,417 ha) of

dry shrub on BLM- and FS-administered lands, of

which 93 percent is the big sagebrush-cool PVT.

The acreage scheduled for weed control (inconsistency in cluster 3 for Alternatives 3 and 6; see

rangeland assumption 6) would accommodate

control of the weed acreage currently present on

this dry shrub.

Cluster 5 — Prediction: Prevention of further infestation of dry shrub and some reclaiming of dry shrub

from weeds by year 100. Noxious weeds with

prevalence in dry shrub in this cluster are yellow

starthistle, rush skeletonweed, medusahead,

halogeton, and cheatgrass. The IWM emphasis of

Alternative 4 would be strong, targeting all weed

species mentioned. Also, acreage scheduled for

weed control would be adequate to reclaim some

dry shrub that is currently dominated by cheatgrass, medusahead, or other noxious weeds. The

emphasis would be on control (reduction in infestation size) and rehabilitation. The high acreage

scheduled for livestock management should help

prevent reinvasion of weed-controlled areas.

Cluster 6 — Prediction: Minor further infestation

of dry shrub. Noxious weeds with prevalence in

dry shrub in this cluster are Dyers woad, diffuse

knapweed, yellow starthistle, medusahead, rush

skeletonweed, and cheatgrass. The IWM emphasis

of Alternative 4 would be strong in this cluster,

but would emphasize control (reduction in infestation size) rather than prevention of spread and

eradication. Cheatgrass and medusahead would be

the primary target of weed control efforts because

of their prevalence. However, IWM steps 1

through 4 (table 2.42) would not be emphasized

under Alternative 4, which would result in low

emphasis on greenstripping. This is a technique

for preventing further spread of annual grasses

into native shrub-steppe vegetation (dry shrub).

Reseeding of burned areas that are now dominated by cheatgrass and/or medusahead, or are

expected to be dominated by them, would be a

focus of weed control acreage in this cluster.

Alternative 5 Effectiveness

(Dry Shrub, UCRB)

Overall rank: 1.94, at the high end of Moderate

effectiveness.

Effectiveness in preventing further infestation of

dry shrub:

Range clusters 2 and 3: High

Range clusters 5 and 6: Poor

Clusters 2 and 3 — See discussion for these clusters under Alternative 4.

Cluster 5 — Prediction: Further infestation of dry

shrub. Noxious weeds with prevalence in dry

shrub in this cluster are yellow starthistle, rush

skeletonweed, medusahead, halogeton, and cheatgrass. The IWM emphasis of this alternative in

this cluster is stronger than Alternative 3 but the

weed control acreage scheduled is much less than

in Alternative 3. In addition to having less areas in

weed control, this alternative would only target

cheatgrass and halogeton. Thus, little weed control would be directed to the other noxious weeds

and their spread would continue. Weed control

efforts should, however, result in some reseeding

and rehabilitation of areas currently dominated by

cheatgrass (and medusahead, if present in association with cheatgrass) and halogeton. Some greenstripping will be implemented, with the same

emphasis as reseeding and rehabilitation, which

will help prevent the spread of annual grasses.

Even with these efforts, further spread of noxious

weeds into dry shrub would be expected.

Landscape Ecology
Cluster 6 — Prediction: Further infestation of dry

shrub. Noxious weeds with prevalence in dry

shrub in this cluster are Dyers woad, diffuse knapweed, yellow starthistle, medusahead, rush skeletonweed, and cheatgrass. The IWM emphasis of

Alternative 5 would not be as strong in this cluster as Alternative 4. Cheatgrass and Dyers woad

would be the target of weed control efforts, which

would result in some further infestation of dry

shrub by the other species. Without an emphases

on IWM steps 1 through 4 (table 2.42), there

would not be great emphasis on greenstripping.

This is a technique for preventing further spread

of annual grasses into native shrub-steppe vegetation (dry shrub). Reseeding of burned areas that

are now dominated by cheatgrass and/or medusahead, or are expected to be dominated by them,

would be a focus of weed control acreage in this

cluster.

Alternative 6 Effectiveness

(Dry Shrub, UCRB)

Overall rank: 2.19, at the low end of High effectiveness.

Effectiveness in preventing further infestation of

dry shrub:

Range clusters 2 and 3: High

Range clusters 5 and 6: Moderate

Clusters 2 and 3 — See discussion for these clusters under Alternative 4.

Cluster 5 — Prediction: Further infestation of dry

shrub. Noxious weeds with prevalence in dry

shrub in this cluster are yellow starthistle, rush

skeletonweed, medusahead, halogeton, and cheatgrass. Although the IWM emphasis of this alternative in this cluster would be stronger than

Alternative 4, and all weed species mentioned

would be targeted, the acreage scheduled for weed

control would be one-third that of Alternative 4.

The predicted result is that weed management,

which in Alternative 6 focuses on control

(through reduction in infestation size) and reseeding, would be directed more toward areas where

rehabilitation success is judged high. This means

that areas in lower precipitation zones would

undoubtedly not receive control efforts because

rehabilitation success would be less there. The

high acreage scheduled for livestock management

under Alternative 6, however, should help prevent

reinvasion of weed-controlled areas.

Cluster 6 — Prediction: Some further infestation of

dry shrub. Further infestation would be at a

greater level than under Alternative 4. Noxious

weeds with prevalence in dry shrub in this cluster

are Dyers woad, diffuse knapweed, yellow starthistle, medusahead, rush skeletonweed, and cheatgrass. The IWM emphasis of this alternative

would be strong in this cluster, but would emphasize control (through reduction in infestation size)

rather than prevention of spread and eradication.

The acreage scheduled for weed control, which

would be less than Alternative 4, would not prevent further spread of cheatgrass and noxious

weeds. Cheatgrass, medusahead, and noxious

weeds growing in association with these two

species would be targets of weed control efforts.

Without emphasis on IWM steps 1 through 4,

there would not be high emphasis on greenstripping; this is a technique for preventing further

spread of annual grasses into native shrub-steppe

vegetation (dry shrub). Reseeding of burned areas

that are now dominated by cheatgrass and/or

medusahead, or are expected to be dominated by

them, would be a focus of weed control acreage in

this cluster.

Alternative 7 Effectiveness

(Dry Shrub, UCRB)

Overall rank: 1.62, which is Moderate.

Effectiveness in preventing further infestation of

dry shrub:

Range cluster 3: High

Range cluster 2: Moderate

Range clusters 5 and 6: Poor

Cluster 2 — Prediction: Minor further infestation

of dry shrub by year 100. Of the approximately

22,000 acres (8,907 ha) of dry shrub on BLM- and

Landscape Ecology 26?
FS-administered lands in this cluster as a whole, 88

percent is in reserves. Since there is no weed control acreage proposed under this alternative in this

cluster, if noxious weeds invade the dry shrub in

reserves, eradicating them will be difficult.

Cluster 3 — Prediction: Prevention of further infestation of dry shrub and, by year 100, some reclaiming of dry shrub. There are approximately 3,500

acres (1,417 ha) of dry shrub in this cluster. The

portion in reserves appears to be in the Lower

Salmon subbasin, and is in the big sagebrush-cool

PVT; noxious weeds are not prevalent here.

Cluster 5 — Prediction: Further infestation of dry

shrub, particularly in reserves. Noxious weeds with

prevalence in dry shrub in this cluster are yellow

starthistle, rush skeletonweed, medusahead,

halogeton, and cheatgrass. The IWM emphasis of

Alternative 7 would not be as strong in this cluster as in Alternative 4. Cheatgrass and halogeton

would be the only species targeted for weed control. These two species are already present in the

dry shrub in reserves, a substantive portion of

which is located in the Upper Owyhee, Bruneau,

and Salmon Falls subbasins. There would be concern in dry shrub in these subbasins regarding the

substantial areal extent of clay soils, which make

the area susceptible to medusahead invasion and

dominance. Outside reserves, the prediction is

that the acreage scheduled for weed control will

permit minor further infestation of dry shrub.

Outside reserves, weed control efforts of Alternative 7 will result in reseeding and rehabilitation of

areas currently dominated by cheatgrass and/or

medusahead (if growing in association with cheatgrass). The acreage scheduled for livestock management outside reserves would be adequate to

reduce the risk of seeding failures and also reduce

the risk of new infestations.

Cluster 6 — Prediction: Further infestation of dry

shrub, particularly in reserves. The effects of noxious weeds and cheatgrass in this cluster differ,

depending largely on whether they lie inside

reserves or outside reserves. On reserves, the dry

shrub exists primarily in the Lake Walcott and

American Falls subbasins, which already have a

cheatgrass component that is predicted to remain

and spread. Outside reserves, cheatgrass, medusahead, and the other noxious weeds would be controlled somewhat through reductions in infestation size; however, prevention of spread and eradication of small infestations would not be an

emphasis of IWM in this alternative.

Cool Shrub Potential Vegetation Group

(EEIS)

The effectiveness of the alternatives to prevent further infestations of the cool shrub potential vegetation group in the Eastside EIS area is ranked by

range cluster and alternative in table 2.47.

Table 2.47 — Rank of the effectiveness of alternatives in controlling noxious weeds and cheatgrass in the

cool shrub potential vegetation group by range cluster and alternative (Eastside EIS).1

Rank of Control Effectiveness by Alternative

Range Cluster

1

2

3

4

5

6

Overall rank

0

2

1.75

2.5

0.75

0.5

1.25

0

2

1.75

2.5

0.75

0.5

1.25

0.75

2

1.75

2.75

3

3

2.21

1.5

2

1.75

2.75

2.5

3

2.25

0

2

2

2.5

1.75

3

1.87

1.5

2

1.75

2

1.5

2.5

1.87

0

3

2

2.75

2.5

2

2.04

'0-1 = low effectiveness.

1-2 = moderate effectiveness.

2-3 = high effectiveness.

Ranks should not be compared between clusters, but rather more appropriately within a cluster across alternatives.

268 Landscape Ecology
Alternatives 1 and 2 Effectiveness

(Cool Shrub, EEIS)

Overall rank: 1.25, at the low end of Moderate

effectiveness.

Effectiveness in preventing further infestation of

cool shrub:

Range cluster 4: High

Range clusters 2 and 3: Moderate

Range clusters 1,5, and 6: Poor

In clusters 1, 5, and 6, noxious weed control

under these alternatives would be continuation of

the present approach. This approach is fragmented and does not prevent further infestation of cool

shrub by noxious weeds. Although acreage scheduled for weed control would be minor in cluster

4, this cluster has a minor amount of cool shrub

and a negligible noxious weed problem that warrants a high rank of effectiveness.

Although clusters 2 and 3 do not have an extensive noxious weed problem in cool shrub, both

clusters could be further infested (attributable to

no acreage being scheduled for weed control).

Alternative 3 Effectiveness

(Cool Shrub, EEIS)

Overall rank: 2.21, at the low end of High effectiveness.

Effectiveness in preventing further infestation of

cool shrub:

Range clusters 4, 5, and 6: High

Range clusters 2 and 3: Moderate

Range cluster 1: Poor

Cluster 1 — Prediction: Further infestation of cool

shrub. The extent of the additional infestation in

this cluster would be more than in Alternative 4.

In the Eastside EIS area, cluster 1 has arguably the

most extensive noxious weed problem within the

cool shrub PVG. Noxious weeds with prevalence

in cool shrub are diffuse knapweed, yellow starthistle, leafy spurge, and medusahead. The IWM

emphasis of Alternative 3, however, would not be

directed to any of these species for weed control

efforts because PVTs within the cool shrub PVG

are not of high susceptibility to invasion by these

species. However, the assumption is that the

acreage scheduled for weed control would be

directed first to the high disturbance areas such as

roads near cool shrub, probably to yellow starthistle and diffuse knapweed, and second to control

of medusahead and leafy spurge. Given the rapid

spread rates of diffuse knapweed and yellow

starthistle particularly, and the relatively large

acreage of medusahead in this cluster on BLMand FS-administered lands, the acreage scheduled

for weed control would not prevent these species

from spreading.

Medusahead is often located in the understory of

western juniper woodlands in this cluster. Western

juniper woodlands in this cluster are a priority for

treatment particularly by burning. Much of the

approximately 67,500 acres (27,328 ha) of prescribed burning proposed per decade for this

alternative in this cluster is assumed to be prioritized to western juniper; this level would be less

than in Alternative 4. There is some expectation

that prescribed burning of western juniper woodlands would mostly be undertaken on areas where

medusahead does not dominate the understory.

Prescribed burning of western juniper woodlands

where medusahead is present could result in

either: (1) a decline in medusahead density, at

least temporarily, if burning were implemented at

medusahead's vulnerable phenological stage; or (2)

an opening of new areas to potential invasion by

medusahead and perhaps the other noxious weed

species. It is assumed, however, that prescribed

burning would be applied judiciously so that

medusahead spread would not be promoted.

Clusters 2 and 4 — See discussion for these clusters under Alternative 4.

Cluster 3 — See discussion for cluster 3 under

Alternative 4. The only difference here is that this

alternative would schedule a very minor acreage

for weed control (inconsistency; see rangeland

assumption 6).

Landscape Ecology 269
Cluster 5 — Prediction: Prevention of further infestation of cool shrub and, by year 100, some reclaiming of cool shrub. Noxious weeds with prevalence

in the cool shrub in this cluster are medusahead,

and possibly rush skeletonweed, tansy ragwort,

and diffuse knapweed. Leafy spurge is not yet a

problem in cool shrub in this cluster, but is predicted to be in the future and would require control efforts.

Although the thrust of this alternative in regard to

IWM is not as strong as in alternative 4, the

acreage scheduled for weed control is greater than

alternative 4. Because no PVTs in the cool shrub

PVGs are labeled of high susceptibility to invasions by any weeds in this cluster, the target of

weed control efforts would not include any of the

problematic weeds listed above. However, the

assumption is that the acreage scheduled would

target medusahead, which is the major problem

weed in this cluster. The IWM steps 5 to 7 focus

efforts on control (reduction in infestation size)

and reseeding after initial weed control, and these

efforts would be prioritized to medusaheadinfested areas. Even with these efforts, eliminating

medusahead from cool shrub areas is not feasible

at present; however, reseeding with native or

"desired" exotic species could result in reintroducing these species to the areas.

It was assumed that the 140,000 acres (56,680 ha)

scheduled for prescribed burning per decade

would be applied judiciously, particularly in areas

having cool shrub and clayey soils known to be

susceptible to medusahead invasion. Another

assumption was that some of this prescribed burning would be directed at controlling medusahead

in preparation for reseeding efforts.

Cluster 6 — Prediction: Prevention of further infestation in cool shrub and reclaiming of some cool

shrub by year 100. Noxious weeds with prevalence

in cool shrub in this cluster are medusahead, leafy

spurge, cheatgrass, and possibly diffuse knapweed

and tansy ragwort. The IWM emphasis of Alternative 3 would not be as strong as Alternative 4,

and only cheatgrass of the five weeds listed would

be a priority for weed control efforts. However,

medusahead, which is often found in proximity to

or in association with cheatgrass, is also expected

to receive weed control efforts.

The acreage scheduled for weed control would

permit control (reduction in infestation size) of

medusahead and cheatgrass. Seeding would be an

emphasis after initial weed control, particularly in

the drier portions. Control of medusahead and

cheatgrass in preparation for seeding was assumed

to require prescribed burning, and the proposed

135,000 acres (54,656 ha) of prescribed burning

per decade would be adequate for this purpose.

Leafy spurge and the other weeds listed would

probably infest cool shrub, but cool shrub in total

is predicted to increase.

Alternative 4 Effectiveness

(Cool Shrub, EEIS)

Overall rank: 2.25, at the low end of High effectiveness.

Effectiveness in preventing further infestation of

cool shrub:

Range clusters 4, 5, and 6: High

Range clusters 1, 2, and 3: Moderate

Cluster 1 — Prediction: Further infestation of cool

shrub. In the Eastside EIS area, this cluster has

arguably the most extensive noxious weed problem within the cool shrub PVG. Noxious weeds

with prevalence in cool shrub in this cluster are

diffuse knapweed, yellow starthistle, leafy spurge,

and medusahead. These species would be the priority for weed control efforts under this alternative. Given the rapid spread rates of diffuse knapweed and yellow starthistle particularly, and the

relatively large acreage of medusahead in this cluster on BLM- and FS-administered lands, the

acreage scheduled for weed control would not prevent these species from spreading.

Medusahead is often located in the understory of

western juniper woodlands in this cluster. These

woodlands would be a priority for treatment, particularly by burning; it is assumed that much of

the 110,000 acres (44,534 ha) of prescribed

278 Landscape Ecology
burning per decade under Alternative 4 would be

targeted to western juniper. There is some expectation that areas where medusahead does not dominate the understory would be the target of most

prescribed burning of western juniper woodlands.

Prescribed burning of western juniper woodlands

where medusahead is present could result in either:

(1) a decline in medusahead density, at least temporarily, if the burning were implemented at the

vulnerable phenological stage of medusahead; or

(2) an opening of new areas to potential invasion

by medusahead and perhaps the other noxious

weed species. It is assumed, however, that prescribed burning would be applied judiciously so

that medusahead spread would not be promoted.

Cluster 2 — Prediction: Minor further infestation

of cool shrub. The noxious weed infestation of cool

shrub in this cluster is predicted to be negligible

at the present time, and there is no acreage scheduled for weed control under this alternative. There

is concern that diffuse knapweed in central Washington could, or possibly already has, establish

and spread along roads near cool shrub. Without

any weed control, diffuse knapweed would spread.

Cluster 3 — Prediction: Minor further infestation

of cool shrub. Noxious weeds proposed as infesting

some cool shrub in this cluster are tansy ragwort,

whitetop, diffuse knapweed, leafy spurge, and

medusahead. Although not listed in appendix 2L

table 2L.3, medusahead is suspected to be present

on cool shrub in this cluster, particularly in the

Powder subbasin where there is substantial clay

soil that overlaps the distribution of cool shrub.

Based on current information, however, the

acreage of cool shrub infested by these weeds is

low. Given that no acreage is proposed for weed

control for Alternative 4 in this cluster, weeds that

are present will spread.

Cluster 4 — Prediction: Prevention of further infestation of cool shrub and some reclaiming of cool

shrub by year 100. There is presently little noxious

weed problem in cool shrub in this cluster, and

additionally, only approximately 12,400 acres

(5,020 ha) of cool shrub are in this cluster. Most

of the cool shrub in this cluster is in the BLM s

Spokane District. Although the level of acreage

scheduled for weed control in cool shrub would

be minor in Alternative 4 (inconsistency; see

rangeland assumption 6), it should be adequate to

prevent further infestation.

Cluster 5 — Prediction: Prevention of further infestation of cool shrub and some reclaiming of cool

shrub by year 100. Noxious weeds with prevalence

in cool shrub in this cluster are medusahead, and

possibly rush skeletonweed, tansy ragwort, and

diffuse knapweed. Although not yet a problem in

this cluster's cool shrub, leafy spurge is predicted

to be present in the future and would require control efforts. The acreage scheduled for weed control is predicted to be targeted to medusahead, the

major problem weed here. The IWM emphasis of

this alternative would be strong, with control

(reduction in infestation size) and reseeding after

initial weed control priorities for medusaheadinfested areas. Although eliminating medusahead

from cool shrub areas is not presently feasible,

reseeding with native or "desired" exotic species

could result in reintroduction of these species into

the areas.

It is assumed that the 142,500 acres (57,692 ha)

scheduled per decade for prescribed burning

would be applied judiciously, particularly in areas

having cool shrub with clayey soils known to be

susceptible to medusahead invasion. Another

assumption is that some of this prescribed burning would be used to control medusahead in

preparation for reseeding efforts.

Cluster 6 — Prediction: Prevention of further infestation of cool shrub and reclaiming of some cool

shrub by year 100. Noxious weeds with prevalence

in cool shrub in this cluster are medusahead, leafy

spurge, cheatgrass, and possibly diffuse knapweed

and tansy ragwort. The IWM emphasis of

Alternative 4 would be strong and the acreage

scheduled for weed control sufficient to control

medusahead and cheatgrass and the other weeds

listed. Seeding would be an emphasis after initial

weed control, particularly in the drier portions,

where the majority of weed acreage is expected to

be located. The 132,500 acres (53,644 ha) of preLandscape Ecology 271
scribed burning proposed per decade would be

adequate to control medusahead and cheatgrass in

preparation for reseeding.

Alternative 5 Effectiveness

(Cool Shrub, EEIS)

Overall rank: 1.87, at the high end of Moderate

effectiveness.

Effectiveness in preventing further infestation of

cool shrub:

Range clusters 4 and 6: High

Range clusters 2, 3, and 5: Moderate

Range cluster 1: Poor

Cluster 1 — Prediction: Further infestation of cool

shrub. The extent of further infestation would be

greater than in Alternative 3. In the Eastside EIS

area, this cluster has arguably the most extensive

noxious weed problem within cool shrub.

Noxious weeds with prevalence in cool shrub are

diffuse knapweed, yellow starthistle, leafy spurge,

and medusahead. None of these species would be

the target of weed control efforts because PVTs in

the cool shrub PVG are not of high susceptibility

to invasion by any of these species.

Two assumptions for this alternative and cluster

were that: (1) the acreage scheduled for weed control would be directed primarily to the high disturbance areas such as roads near cool shrub,

probably to yellow starthistle and diffuse knapweed; and (2) not much weed control acreage

would be targeted to medusahead and leafy

spurge. Given the rapid spread rates of diffuse

knapweed and yellow starthistle particularly, and

the relatively large acreage of medusahead in this

cluster on BLM- and FS-administered lands, the

acreage scheduled for weed control would not prevent these species from spreading.

Medusahead is often located in the understory of

western juniper woodlands in this cluster. These

woodlands would be a priority for treatment, particularly burning. It was assumed that much of

the 45,000 acres (18,219 ha) of prescribed burning scheduled per decade for Alternative 5 would

target western juniper; this level of prescribed

burning would be less than in Alternative 3.

There is some expectation that prescribed burning

of western juniper woodlands would mostly be

undertaken on areas where medusahead does not

dominate the understory. Prescribed burning of

western juniper woodlands where medusahead is

present could result in either: (1) a decline in

medusahead density, at least temporarily, if the

burning were implemented at medusahead's vulnerable phenological stage; or (2) an opening of

new areas to potential invasion by medusahead

and perhaps the other noxious weed species. It

was assumed, however, that prescribed burning

would be applied judiciously so that medusahead

spread would not be promoted.

Cluster 2 — Prediction: Minor further infestation

of cool shrub. The noxious weed infestation of cool

shrub in this cluster is predicted to be negligible

at the present time, and no acreage would be

scheduled for weed control in this cluster under

Alternative 5. The concern is that diffuse knapweed in central Washington could, or possibly

already has, established and spread along roads

near cool shrub. Without any weed control, diffuse knapweed would spread.

Cluster 3 — Prediction: Minor further infestation

of cool shrub. The acreage scheduled for weed

control in this cluster would be greater in this

alternative than with any other alternative (inconsistency; see rangeland assumption 6). Additional

information on this cluster is included under

Alternative 4.

It is assumed that the acreage scheduled for weed

control (inconsistency; see rangeland assumption

6) would be directed primarily to high disturbance areas such as roads in the proximity of cool

shrub. If necessary, some acreage would be directed to reseeding of medusahead-infested cool

shrub, even though there are no PVTs within the

cool shrub PVG that are of high susceptibility to

invasion by medusahead.

Cluster 4 — See discussion for this cluster under

Alternative 4.

272 Landscape Ecology
Cluster 5 — Prediction: Further infestation of cool

shrub. Further infestation would be at a slightly

slower rate than in Alternative 6. The species that

particularly would contribute to the increase

would be medusahead. Additional information

about this cluster is provided under Alternative 6.

The IWM emphasis of this alternative would not

place priority on weed control of any of the weed

species listed for this cluster in cool shrub, but the

scheduled weed control acreage is assumed to be

targeted to medusahead.

Cluster 6 — See discussion for this cluster under

Alternative 3.

The prescribed burning acreage of 100,000 acres

(40,486 ha) per decade would be slightly less than

in Alternative 3, but still predicted as adequate for

control of medusahead and cheatgrass in preparation for seeding efforts.

Alternative 6 Effectiveness

(Cool Shrub, EEIS)

Overall rank: 1.87, at the high end of Moderate

effectiveness.

Effectiveness in preventing further infestation of

cool shrub:

Range cluster 6: High

Range clusters 1 through 5: Moderate

Cluster 1 — See discussion for this cluster under

Alternative 4, which would be similar except

Alternative 6 would schedule a slightly greater

level of prescribed burning [about 117,500 acres

(47,571 ha) per decade].

Clusters 2 and 3 — See discussion for these clusters under Alternative 4.

Cluster 4 — Prediction: Minor further infestation

of cool shrub. There would essentially be no weed

control scheduled for this cluster under this alternative. The fragmented nature of the BLM- and

FS-administered lands in the cool shrub in this

cluster, and their close proximity to Other lands,

makes them a greater risk for noxious weed invasion. Also, the lack of livestock management in

this cluster would not support maintaining a vigorous stand of vegetation that would resist weed

invasion. For additional information about this

cluster, see its discussion under Alternative 4.

Cluster 5 — Prediction: Further infestation of cool

shrub, particularly by medusahead. Noxious weeds

with prevalence in cool shrub in this cluster are

medusahead, and possibly rush skeletonweed,

tansy ragwort, and diffuse knapweed. Although

not a problem yet in cool shrub in this cluster,

leafy spurge may invade in the future, in which

case infestations would require control efforts.

The acreage scheduled for weed control under

Alternative 6 is predicted to be targeted to

medusahead, the major problem weed in this cluster. However, the level of control projected for

medusahead would not curtail its spread and

infestation size. Although eliminating medusahead

from cool shrub areas is not presently feasible,

reseeding with native or "desired" exotic species

could reintroduce these species into medusaheadinfested areas. It is assumed that the 142,500 acres

(57,692 ha) scheduled for prescribed burning per

decade would be applied judiciously, particularly

in areas having cool shrub on clayey soils known

to be susceptible to medusahead invasion. A further assumption is that some prescribed burning

would be used to control medusahead in preparation for reseeding efforts.

Cluster 6 — Prediction: Some reclaiming of cool

shrub from weeds by year 100. Noxious weeds with

prevalence in cool shrub in this cluster are

medusahead, leafy spurge, cheatgrass, and possibly

diffuse knapweed and tansy ragwort. The IWM

emphasis of this alternative in this cluster would

be as strong as in Alternative 4. The acreage

scheduled for weed control, however, would be

less than Alternative 4 and targeted toward control (reduction in infestation size) of medusahead,

cheatgrass, and the other weeds listed. The reduction in weed acreage attributable to control and

seeding is expected to outpace the increase in

weed acreage attributable to spread, but not to the

same extent as in Alternative 4. Some cool shrub

Landscape Ecology 273
would be reclaimed, but on less acreage than for

Alternative 4. Seeding, particularly in the drier

portions, would be an emphasis after initial weed

control. The 130,000 acres (52,632 ha) of prescribed burning scheduled per decade under

Alternative 6 would be adequate for the control

assumed to be needed for medusahead and cheatgrass in preparation for seeding.

Alternative 7 Effectiveness

(Cool Shrub, EEIS)

Overall rank: 2.04, at the low end of High effectiveness.

Effectiveness in preventing further infestation of

cool shrub:

Range clusters 2, 4, and 5: High

Range clusters 3 and 6: Moderate

Range cluster 1: Poor

Cluster 1 — Prediction: Further infestation of cool

shrub. Of approximately 887,000 acres (359,109

ha) of cool shrub in this cluster as a whole, only 6

percent or approximately 51,700 acres (20,931

ha), would be in reserves. The acreage scheduled

for weed control in Alternative 7 would be roughly one-half that of Alternative 3, but would be

directed to roughly the same land mass because

nearly all the cool shrub is located outside

reserves. Much of the cool shrub in reserves is

located in the Lost and Goose Lake subbasins,

which are strongly suspected of already having

medusahead invasion due to their clayey soils and

the known presence of medusahead in those

HUCs.

Cluster 2 — Prediction: Prevention of further infestation of cool shrub by year 100 and reclaiming of

some cool shrub that is currently infested. Approximately 96 percent of the approximately 91,000

acres (36,842 ha) of cool shrub in this cluster for

both EIS areas is in reserves. The high amount in

reserves and the very minor noxious weed problem in cool shrub in the Eastside EIS portion of

this cluster would help prevent further infestations. An assumption in this cluster is that disturbances in reserves that would enhance the spread

of weeds would be minor, and also any species in

the reserves such as diffuse knapweed would not

spread appreciably, even along roads. The minor

amount scheduled for weed control outside

reserves (inconsistency; see rangeland assumption

6) should be effective in reducing noxious weed

extents because there is very little cool shrub outside reserves.

Cluster 3 — Prediction: Minor further infestation

of cool shrub. Some cool shrub in this cluster in

the Eastside EIS portion is in reserves, particularly

in the Little Deschutes subbasin. There is concern

in this subbasin relative to diffuse knapweed and

its potential for invasion and spread along existing

roads in the area. Outside reserves, the acreage

scheduled for weed control (inconsistency; see

rangeland assumption 6) would probably be targeted to high disturbance areas near cool shrub

and to medusahead, if necessary.

Cluster 4 — Prediction: Prevention of further infestation of cool shrub and some reclaiming of cool

shrub by year 100. Approximately 64 percent of

the approximately 12,400 acres (5,020 ha) of cool

shrub on BLM- and FS-administered lands in this

cluster would be in reserves. There is not, presently, a noxious weed problem known in this cool

shrub area. The acreage scheduled for weed control, although minor (inconsistency; see rangeland

assumption 6), should prevent further spread of

any noxious weeds outside reserves.

Cluster 5 — Prediction: Prevention of further infestation of cool shrub and some reclaiming of cool

shrub by year 100. The cool shrub within reserves

in the Eastside EIS portion of this cluster is primarily the mountain big sagebrush-mesic-west

PVT and is mostly located in the Middle

Owyhee subbasin. This area does not presently

have much of a noxious weed problem. Noxious

weeds with prevalence in cool shrub in this cluster are medusahead and possibly rush skeletonweed, tansy ragwort, and diffuse knapweed.

Although not a problem yet in cool shrub in this

cluster, leafy spurge will be present in the future

and would require control efforts. No PVTs with274 Landscape Ecology
in the cool shrub PVG are of high susceptibility

to invasion by the weeds listed in this cluster, so

the weeds listed above would not be the target of

weed control efforts. However, it was assumed

that any weed control acreage scheduled would be

targeted to medusahead, which is the major problem weed in this cluster outside reserves. Control

(reduction in infestation size) and reseeding after

initial weed control would be priorities for

medusahead-infested areas. Although eliminating

medusahead from cool shrub areas is not presently

feasible, reseeding with native or "desired" exotic

species could result in reintroducing these species

to the areas.

It is assumed that the 150,000 acres (60,729 ha)

scheduled for prescribed burning per decade

would be applied judiciously, particularly relative

to cool shrub on clayey soils known to be susceptible to medusahead invasion. Another assumption was that some prescribed burning would be

used to control medusahead in preparation for

reseeding efforts.

Cluster 6 — Prediction: Minor further infestation

of cool shrub. There is almost negligible cool shrub

in reserves in this cluster on the Eastside EIS area.

Therefore, almost all of this cluster's cool shrub is

outside reserves, and weed control then would be

roughly at the same level as in Alternative 3. The

acreage scheduled for weed control, however,

would be less than in Alternative 3. The predicted

result of this level of weed management would be

some control (reduction in infestation size) of

cheatgrass and medusahead, but an increase in

extent of other noxious weeds. The end result

would be a slight increase in cool shrub that is

infested with noxious weeds by year 100.

Cool Shrub Potential Vegetation Group

(UCRB)

The effectiveness of the alternatives to prevent

further infestations of the cool shrub potential

vegetation group in the Upper Columbia River

Basin EIS area is ranked by range cluster and

alternative on table 2.48.

Alternatives 1 and 2 Effectiveness

(Cool Shrub, UCRB)

Overall rank: 0.75, which is Low.

Effectiveness in preventing further infestation of

cool shrub:

Range clusters 2, 3, 5, and 6: Poor

In clusters 5 and 6, the manner of controlling

noxious weeds in these alternatives would be to

continue the present approach which is fragmented and does not prevent further infestation of cool

shrub by noxious weeds.

Table 2.48 — Rank of the effectiveness of alternatives in controlling noxious weeds and cheatgrass in the

cool shrub potential vegetation group by range cluster and alternative (Upper Columbia River Basin).'

Range Cluster

Rank of Control Effectiveness by Alternative

2

3

5

6

Overall rank

1

1

0.5

0.5

0.75

1

1

0.5

0.5

0.75

2

1.5

2.75

2

2.06

2

1.5

2.5

2.25

2.06

2

1.75

0.75

1.5

1.5

2

1.5

0

1.75

1.31

2.5

1.5

2.25

1.75

2

'0-1 = low effectiveness.

1-2 = moderate effectiveness.

2-3 = high effectiveness.

Ranks should not be compared between clusters, but rather more appropriately within a cluster across alternatives.

Landscape Ecology 275
Although current noxious weed infestations are of

limited extent in clusters 2 and 3, the lack of any

acreage for weed control would permit the continued spread of noxious weeds.

Alternative 3 Effectiveness

(Cool Shrub, UCRB)

Overall rank: 2.06, at the low end of High

effectiveness.

Effectiveness in preventing further infestation of

cool shrub:

Range cluster 5: High

Range clusters 2, 3, and 6: Moderate

Cluster 2 — Prediction: Minor further infestation

of cool shrub. Although the noxious weed extent in

this cluster is quite minimal, noxious weeds of

concern in cool shrub are thought to be spotted

knapweed and leafy spurge. Further infestation,

although minor, would occur in these clusters as a

result of no acreage being scheduled for weed control under Alternative 3.

Cluster 3 — Prediction: Further infestation of cool

shrub. Noxious weeds with prevalence in cool

shrub in this cluster are proposed as spotted knapweed, leafy spurge, and possibly common crupina.

Available information indicates that the noxious

weed extent is minor on the approximately

55,000 acres (22,267 ha) of cool shrub on BLMand FS-administered land in the Upper Columbia

River Basin portion of this cluster. Since no weed

control would be scheduled in Cluster 3 under

Alternative 3, no attempts would be made to prevent the spread of the three species mentioned.

Cluster 5 — Prediction: Prevention of farther infestation of cool shrub and some reclaiming of cool

shrub by year 100. Noxious weeds with prevalence

on cool shrub in this cluster are medusahead, leafy

spurge, and possibly rush skeletonweed and spotted knapweed. The IWM emphasis of Alternative

3 in this cluster would not prioritize weed control

efforts to any of these species, because the PVTs

in the cool shrub PVG are only moderately susceptible to invasion by the listed species. Although

weed control acreage would be scheduled, it is

assumed the efforts would be directed to all

species, but particularly medusahead and leafy

spurge. In effect, the large acreage scheduled

under Alternative 3 for weed control would tend

to overshadow the relatively weak IWM emphasis

in this cluster. Emphasis in weed control would be

placed on control (reduction in infestation size)

and reseeding of medusahead-infested areas after

initial weed control.

About 337,500 acres (136,640 ha) scheduled for

prescribed burning per decade would be directed

to mountain big sagebrush-dominated areas. As

mentioned below for cluster 6, there is some

expectation that burning of mountain big sagebrush, depending on its proximity to the weed

species listed, will enhance noxious weed spread

because microsites for establishment would

become available.

Cluster 6 — Prediction: Minor farther infestation

of cool shrub. Noxious weeds with some extent on

cool shrub in this cluster are leafy spurge, Dyers

woad, medusahead, cheatgrass, and possibly rush

skeletonweed, diffuse knapweed, and spotted

knapweed. The acreage scheduled for weed control would be prioritized in Alternative 3 to Dyers

woad, because PVTs in the cool shrub PVG are of

high susceptibility to invasion by Dyers woad.

Weed control efforts would not be targeted to the

other species mentioned on cool shrub. However,

it is assumed that some acreage, above the level

used for Dyers woad, could be directed toward

the other species.

A concern is that leafy spurge is present and is

probably the toughest to control of all weeds listed

above. Without an emphasis on leafy spurge, its

potential to spread is great. Because more than one

weed control effort is typically necessary for leafy

spurge control, the available acreage for control of

leafy spurge would need to be directed toward the

same piece of ground in consecutive years.

Prescribed burning in Alternative 3 in cool shrub

is about 62,500 acres (25,304 ha) per decade. It is

expected that burning of mountain big sagebrush,

Landscape Ecology
depending on its proximity to the weed species

listed, would enhance noxious weed spread by

making microsites available for its establishment.

Alternative 4 Effectiveness

(Cool Shrub, UCRB)

Overall rank: 2.06, at the low end of High

effectiveness.

Effectiveness in preventing further infestation of

cool shrub:

Range clusters 5 and 6: High

Range clusters 2 and 3: Moderate

Clusters 2 and 3 — See discussion for these clusters under Alternative 3.

Cluster 5 — Prediction: Prevention of further infestation of cool shrub and some reclaiming of cool

shrub by year 100. Noxious weeds of major concern on cool shrub in this cluster are medusahead,

leafy spurge, and possibly rush skeletonweed and

spotted knapweed. The IWM emphasis of Alternative 4 would permit directing control efforts to

all species above, which would be a stronger

emphasis than Alternative 3. However, the acreage

scheduled for weed control under Alternative 4

would be only two-thirds that of Alternative 3.

Because IWM steps 5 through 7 are emphasized,

reducing the infestation size of medusahead and

leafy spurge would be of greater priority than preventing spread of these species.

The above level of emphasis is expected to result

in some reclaiming of cool shrub because the control rate is expected to slowly outpace the spread

of noxious weeds.

About 342,500 acres (138,664 ha) scheduled for

prescribed burning per decade would be directed

to areas dominated by mountain big sagebrush. As

mentioned below for cluster 6, there is some

expectation that burning of mountain big sagebrush, depending on its proximity to the weed

establishment would become available.

Cluster 6 — Prediction: Prevention of further infestation and some reclaiming of cool shrub by year

100. Noxious weeds with prevalence on cool

shrub in this cluster are leafy spurge, Dyers woad,

medusahead, cheatgrass, and possibly rush skeletonweed, diffuse knapweed, and spotted knapweed. Although the IWM emphasis of Alternative

4 would permit the acreage scheduled for weed

control to be targeted to all these species, the most

likely targets were assumed to be leafy spurge,

medusahead, and Dyers woad. Some weed control

acreage would need to be directed to reseeding of

medusahead-infested areas after initial weed

control.

The toughest weed to control of the seven listed

above may be leafy spurge, which is of some concern because it is already present in cluster 6,

although believed to be in minor amounts on cool

shrub. Because more than one weed control effort

is typically necessary for leafy spurge control, the

available acreage targeting leafy spurge would

need to be directed toward the same land area in

consecutive years.

In Alternative 4, approximately 70,000 acres

(28,340 ha) of prescribed burning would be

scheduled per decade in cool shrub. Depending

on its proximity to the weed species listed, burning of mountain big sagebrush could enhance

noxious weed spread by making microsites available for its establishment.

Some weed control acreage would need to be

directed to reseeding of medusahead-infested areas

in post-control.

Alternative 5 Effectiveness

(Cool Shrub, UCRB)

Overall rank: 1.5, which is Moderate.

Effectiveness in preventing further infestation of

cool shrub:

Range clusters 2, 3, and 6: Moderate

Range cluster 5: Poor

Cluster 2 — Prediction: Minor further infestation

of cool shrub. Although the noxious weed extent in

this cool shrub in this cluster is quite minimal,

noxious weeds of proposed importance are spotted

Landscape Ecology 277
knapweed and leafy spurge. The further infestation is related to the almost negligible acreage

(inconsistency; see rangeland assumption 6) that

would be scheduled for weed control under

Alternative 5.

Cluster 3 — Prediction: Minor further infestation

of cool shrub. See discussion for this cluster under

Alternative 3, which would be similar. There

would be more acreage scheduled for weed control in Alternative 5 than in the other alternatives

for this cluster (inconsistency; see rangeland

assumption 6).

Cluster 5 — Prediction: Further infestation of cool

shrub. Noxious weeds with prevalence on cool

shrub in this cluster are medusahead, leafy spurge,

and possibly rush skeletonweed and spotted knapweed. The IWM emphasis of Alternative 5 would

not target weed control efforts to any of the

species listed, because the PVTs in the cool shrub

PVG are only of moderate susceptibility to invasion by these species. The acreage scheduled for

weed control would likely be directed first towards

high disturbance areas near cool shrub, and then

towards prevention of spread and eradication of

infestations in these high disturbance areas. Any

remaining available acreage could be directed to

actual infestations of the above listed species within cool shrub.

Cluster 6 — Prediction: Further infestation of cool

shrub. The rate of infestation would be more

rapid than in Alternative 3. Reference that alternative for further information on this cluster. In

this cluster, Alternative 5 differs from Alternative

3 by having: (1) much less acreage directed to

livestock management [77,500 acres (31,377 ha)

per decade compared with 220,000 acres (89,069

ha) in Alternative 3] (inconsistency; see rangeland

assumption 6), and (2) much less acreage directed

to prescribed burning [25,000 acres (10,122 ha)

per decade compared with 70,000 acres (28,340

ha) in Alternative 3].

The results of having less acreage in livestock

management are more rapid spread of noxious

weeds in cool shrub compared with Alternative 3,

and possibly greater risk of reinvasion by noxious

weeds after initial weed control. The result of having less acreage in prescribed burning is perhaps

less rapid spread of noxious weeds, such as leafy

spurge, compared with Alternative 3.

Alternative 6 Effectiveness

(Cool Shrub, UCRB)

Overall rank: 1.31, at the low end of Moderate

effectiveness.

Effectiveness in preventing further infestation of

cool shrub:

Range clusters 2, 3, and 6: Moderate

Range cluster 5: Poor

Clusters 2 and 3 — See discussion for these clusters under Alternative 3.

Cluster 5 — Prediction: Further infestation of cool

shrub, particularly by medusahead and leafy spurge.

Although the IWM emphasis of this alternative -

would permit weed control efforts to be directed

to all noxious weeds listed for this cluster, the

acreage would only allow targeting medusahead

and leafy spurge. The acreages of control scheduled, however, would not be sufficient to effectively prevent the spread of these two species.

Cluster 6 — Prediction: Minor further infestation

of cool shrub. See discussion for this cluster under

Alternative 4 for more information. Acreage

scheduled for weed control would be much less in

this cluster than in Alternative 4; also, more

spread of noxious weeds is predicted under this

alternative. The acreage scheduled for prescribed

burning in both alternatives would be almost the

same.

Alternative 7 Effectiveness

(Cool Shrub, UCRB)

Overall rank: 2, at the high end of Moderate

effectiveness.

Effectiveness in preventing further infestation of

cool shrub:

Range clusters 2 and 5: High

Range clusters 3 and 6: Moderate

278 Landscape Ecology
Cluster 2 — Prediction: Prevention of further infestation of cool shrub and some reclaiming of cool

shrub by year 100. Approximately 96 percent of

the cool shrub on BLM- and FS-administered

lands within this cluster in both EIS areas is in

reserves. Whatever noxious weeds are within these

reserves are not expected to spread much; further,

the spread of noxious weeds on cool shrub outside

reserves would be prevented.

Cluster 3 — Prediction: Further infestation of cool

shrub. There would be acreage scheduled under

Alternative 7 for weed control outside reserves,

but of an almost negligible amount (inconsistency; see rangeland assumption 6).

Cluster 5 — Prediction: Prevention of further infestation of cool shrub and some reclaiming of cool shrub

by year 100. Most of the cool shrub within reserves

is in southwest Idaho, which does not yet have a

major problem with medusahead and other noxious weeds in cool shrub. There is concern, however, that medusahead could become more extensive in this area of cool shrub in reserves due to a

prevalence of clay soils in portions of that area. The

acreage scheduled for weed control under Alternative 7 is expected to result in control (reduction in

infestation size) of medusahead and leafy spurge

and reseeding of medusahead-infested areas.

Cluster 6 — Prediction: Minor further infestation

of cool shrub. There are approximately 474,000

acres (191,903 ha) of cool shrub in reserves in this

cluster for both EIS areas, nearly all of which are

in the Upper Columbia River Basin EIS area.

Given available information, leafy spurge is not

proposed as extensive yet in this cool shrub in

reserves. However, concern exists for potential

invasion of this cool shrub in reserves by leafy

spurge and medusahead due to the prevalence of

clayey soils in the area that would be in reserves.

Although the acreage scheduled for weed control

outside reserves would be directed to Dyers woad

only, the assumption is made that not all 30,000

acres (191,903 ha) per decade would be directed

to Dyers woad, but that some could be directed

to the other species. This would include reseeding

of medusahead-infested areas after initial weed

control.

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28Q Landscape Ecology